diff --git a/.eslintignore b/.eslintignore
index 48c498f279..2226cf1fc2 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -2,4 +2,5 @@ coverage/
 mocha.js
 *.fixture.js
 docs/
+out/
 !lib/mocha.js
diff --git a/.gitignore b/.gitignore
index f11fc29c86..7e1edeb748 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,4 +22,5 @@ yarn.lock
 docs/_site
 docs/_dist
 docs/api
+out/
 .vscode/
diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000000..35cee72dcb
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+2.4.3
diff --git a/.travis.yml b/.travis.yml
index 94aa85770e..f6153f6815 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,7 @@
+###
+### .travis.yml
+###
+
 # these are executed in order.  each must pass for the next to be run
 stages:
   - smoke # this ensures a "user" install works properly
@@ -7,7 +11,11 @@ stages:
 
 # defaults
 language: node_js
-node_js: '10'
+node_js: '11'
+addons:
+  apt:
+    packages:
+    - libnotify-bin
 # `nvm install` happens before the cache is restored, which means
 # we must install our own npm elsewhere (`~/npm`)
 before_install: |
@@ -32,7 +40,7 @@ jobs:
 
     - &node
       script: npm start test.node
-      node_js: '9'
+      node_js: '10'
 
     - <<: *node
       node_js: '8'
@@ -67,7 +75,7 @@ jobs:
           - node_modules # npm install, unlike npm ci, doesn't wipe node_modules
 
     - <<: *smoke
-      node_js: '9'
+      node_js: '10'
 
     - <<: *smoke
       node_js: '8'
diff --git a/Gemfile b/Gemfile
index 743d18eca7..1a8c10648c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,3 @@
 source "https://rubygems.org"
 # Added at 2017-12-05 23:01:55 -0800 by boneskull:
-gem "jekyll", "~> 3.6"
+gem "jekyll", ">= 3.8.4"
diff --git a/Gemfile.lock b/Gemfile.lock
index ad15098a0c..dd897f793e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -14,7 +14,7 @@ GEM
     http_parser.rb (0.6.0)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
-    jekyll (3.8.3)
+    jekyll (3.8.4)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
@@ -29,25 +29,25 @@ GEM
       safe_yaml (~> 1.0)
     jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
-    jekyll-watch (2.0.0)
+    jekyll-watch (2.1.2)
       listen (~> 3.0)
     kramdown (1.17.0)
-    liquid (4.0.0)
+    liquid (4.0.1)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
       ruby_dep (~> 1.2)
     mercenary (0.3.6)
-    pathutil (0.16.1)
+    pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (3.0.3)
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    rouge (3.2.1)
+    rouge (3.3.0)
     ruby_dep (1.5.0)
     safe_yaml (1.0.4)
-    sass (3.5.7)
+    sass (3.6.0)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -57,7 +57,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  jekyll (~> 3.6)
+  jekyll (>= 3.8.4)
 
 BUNDLED WITH
-   1.16.1
+   1.16.6
diff --git a/MAINTAINERS.md b/MAINTAINERS.md
index bee04f42d1..55e5436cfc 100644
--- a/MAINTAINERS.md
+++ b/MAINTAINERS.md
@@ -279,18 +279,16 @@ This is not necessarily ideal, and we should consider another method of using br
 1. Decide whether this is a `patch`, `minor`, or `major` release by the PRs which have been merged since the last release.
 1. Checkout `master` in your working copy & pull.
 1. Modify `CHANGELOG.md`; follow the existing conventions in that file.  Commit this file only; add `[ci skip]` to the commit message to avoid a build.
-1. Use `npm version` to bump the version; see `npm version --help` for more info.  (Hint--use `-m`: e.g. `npm version patch -m 'Release v%s'`)
-1. Push `master` to origin with your new tag; e.g. `git push origin master --tags`
+1. Use `npm version` (use `npm@6+`) to bump the version; see `npm version --help` for more info.  (Hint--use `-m`: e.g., `npm version patch -m 'Release v%s'`)
+1. Push `master` to `origin` with your new tag; e.g. `git push origin master --tags`
 1. Copy & paste the added lines to a new GitHub "release".  Be sure to add any missing link references (use "preview" button).  Save release as draft.
 1. Meanwhile, you can check [the build](https://travis-ci.org/mochajs/mocha) on Travis-CI.
-1. Once it's green and you're satisfied with the release notes, open your draft release on GitHub, then click "publish"
+1. Once the build is green, and you're satisfied with the release notes, open your draft release on GitHub, then click "publish."
 1. Back in your working copy, run `npm publish`.
-1. Announce the update on Twitter or just tell your dog or something.
+1. Announce the update on Twitter or just tell your dog or something.  New releases will be automatically tweeted by [@b0neskull](https://twitter.com/b0neskull).
 
 *Note: there are too many steps above.*
 
-> As of this writing, `npm version` (using npm@5) is not working well, and you may have to tag manually.  Commit the change to the version in `package.json` with a message of the format `Release vX.Y.Z`, then tag the changeset using `vX.Y.Z`.
-
 ## Projects
 
 There are [Projects](https://github.com/mochajs/mocha/projects), but we haven't yet settled on how to use them.
diff --git a/appveyor.yml b/appveyor.yml
index 2d2e1e459d..e9f8eba0c0 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,27 +1,71 @@
-platform:
-  - x64
+###
+### appveyor.yml
+###
+
+## General configuration
+version: '{build}'
+skip_commits:
+  message: /\[ci\s+skip\]/
+
+## Environment configuration
+shallow_clone: true
+clone_depth: 1
 environment:
   matrix:
+    - nodejs_version: '11'
     - nodejs_version: '10'
-    - nodejs_version: '9'
     - nodejs_version: '8'
     - nodejs_version: '6'
+matrix:
+  fast_finish: true
 install:
+  ## Manual Growl install
+  - ps: Add-AppveyorMessage "Installing Growl..."
+  - ps: $exePath = "$($env:USERPROFILE)\GrowlInstaller.exe"
+  - ps: (New-Object Net.WebClient).DownloadFile('http://www.growlforwindows.com/gfw/downloads/GrowlInstaller.exe', $exePath)
+  - ps: mkdir C:\GrowlInstaller | out-null
+  - ps: 7z x $exePath -oC:\GrowlInstaller | out-null
+  - ps: cmd /c start /wait msiexec /i C:\GrowlInstaller\Growl_v2.0.msi /quiet
+  - ps: $env:path = "C:\Program Files (x86)\Growl for Windows;$env:path"
+  ## Node-related installs
+  - ps: Add-AppveyorMessage "Installing Node..."
+  - set PATH=%APPDATA%\npm;C:\MinGW\bin;%PATH%
   - ps: Install-Product node $env:nodejs_version x64
-  - set CI=true
-  - set PATH=%APPDATA%\npm;c:\MinGW\bin;%PATH%
+  - ps: Add-AppveyorMessage "Installing npm..."
   - npm install -g npm@^5
+  ## Mocha-related package installs
+  - ps: Add-AppveyorMessage "Installing Mocha dependencies..."
   - npm ci --ignore-scripts
-matrix:
-  fast_finish: true
-build: off
-version: '{build}'
-shallow_clone: true
-clone_depth: 1
+
+## Build configuration
+platform:
+  - x64
+build: script
+before_build:
+  ## Growl requires some time before it's ready to handle notifications
+  - ps: Start-Process -NoNewWindow Growl
+  - ps: Add-AppveyorMessage "Started Growl service..."
+  - ps: Start-Sleep -Milliseconds 2000
+build_script:
+  ## Placeholder command
+  - ps: Start-Sleep -Milliseconds 0
+  #- ps: Add-AppveyorMessage "Verify Growl responding..."
+  #- ps: growlnotify test
+
+## Test configuration
+before_test:
+  - set CI=true
 test_script:
+  - ps: Add-AppveyorMessage "Displaying version information"
   - node --version
   - npm --version
+  - ps: Add-AppveyorMessage "Running tests..."
   - npm start test.node
-skip_commits:
-  message: /\[ci\s+skip\]/
+  - ps: Add-AppveyorMessage "Done"
 
+## Notifications
+notifications:
+  - provider: Email
+    on_build_success: false
+    on_build_failure: false
+    on_build_status_changed: false
diff --git a/bin/_mocha b/bin/_mocha
index 41e9871b76..742c5d70d5 100755
--- a/bin/_mocha
+++ b/bin/_mocha
@@ -157,9 +157,17 @@ program
   .option('-f, --fgrep <string>', 'only run tests containing <string>')
   .option('-gc, --expose-gc', 'expose gc extension')
   .option('-i, --invert', 'inverts --grep and --fgrep matches')
-  .option('-r, --require <name>', 'require the given module')
-  .option('-s, --slow <ms>', '"slow" test threshold in milliseconds [75]')
-  .option('-t, --timeout <ms>', 'set test-case timeout in milliseconds [2000]')
+  .option('-r, --require <name>', 'require the given module', [])
+  .option(
+    '-s, --slow <ms>',
+    'specify "slow" test threshold in milliseconds',
+    75
+  )
+  .option(
+    '-t, --timeout <ms>',
+    'specify test timeout threshold in milliseconds',
+    2000
+  )
   .option(
     '-u, --ui <name>',
     `specify user-interface (${interfaceNames.join('|')})`,
@@ -204,13 +212,16 @@ program
     '--inspect-brk',
     'activate devtools in chrome and break on the first line'
   )
-  .option('--interfaces', 'display available interfaces')
+  .option('--interfaces', 'output provided interfaces and exit')
   .option('--no-deprecation', 'silence deprecation warnings')
   .option(
     '--exit',
     'force shutdown of the event loop after test run: mocha will call process.exit'
   )
-  .option('--no-timeouts', 'disables timeouts, given implicitly with --debug')
+  .option(
+    '--no-timeouts',
+    'disables timeouts, given implicitly with --debug/--inspect'
+  )
   .option('--no-warnings', 'silence all node process warnings')
   .option('--opts <path>', 'specify opts path', 'test/mocha.opts')
   .option('--perf-basic-prof', 'enable perf linux profiler (basic support)')
@@ -218,10 +229,11 @@ program
   .option('--prof', 'log statistical profiling information')
   .option('--log-timer-events', 'Time events including external callbacks')
   .option('--recursive', 'include sub directories')
-  .option('--reporters', 'display available reporters')
+  .option('--reporters', 'output provided reporters and exit')
   .option(
     '--retries <times>',
-    'set numbers of time to retry a failed test case'
+    'specify number of times to retry a failed test case',
+    0
   )
   .option(
     '--throw-deprecation',
@@ -246,11 +258,16 @@ program
   )
   .option(
     '--file <file>',
-    'include a file to be ran during the suite',
+    'adds file be loaded prior to suite execution',
     collect,
     []
   )
-  .option('--exclude <file>', 'a file or glob pattern to ignore', collect, []);
+  .option(
+    '--exclude <file>',
+    'adds file or glob pattern to ignore',
+    collect,
+    []
+  );
 
 program._name = 'mocha';
 
diff --git a/bin/options.js b/bin/options.js
index a25a18e28e..0c27ae5fa9 100644
--- a/bin/options.js
+++ b/bin/options.js
@@ -13,9 +13,54 @@ const fs = require('fs');
 module.exports = getOptions;
 
 /**
- * Get options.
+ * Default pathname for run-control file.
+ *
+ * @constant
+ * @type {string}
+ * @default
  */
+const defaultPathname = 'test/mocha.opts';
 
+/**
+ * Reads contents of the run-control file.
+ *
+ * @private
+ * @param {string} pathname - Pathname of run-control file.
+ * @returns {string} file contents
+ */
+function readOptionsFile(pathname) {
+  return fs.readFileSync(pathname, 'utf8');
+}
+
+/**
+ * Parses options read from run-control file.
+ *
+ * @private
+ * @param {string} content - Content read from run-control file.
+ * @returns {string[]} cmdline options (and associated arguments)
+ */
+function parseOptions(content) {
+  /*
+   * Replaces comments with empty strings
+   * Replaces escaped spaces (e.g., 'xxx\ yyy') with HTML space
+   * Splits on whitespace, creating array of substrings
+   * Filters empty string elements from array
+   * Replaces any HTML space with space
+   */
+  return content
+    .replace(/^#.*$/gm, '')
+    .replace(/\\\s/g, '%20')
+    .split(/\s/)
+    .filter(Boolean)
+    .map(value => value.replace(/%20/g, ' '));
+}
+
+/**
+ * Prepends options from run-control file to the command line arguments.
+ *
+ * @public
+ * @see {@link https://mochajs.org/#mochaopts|mocha.opts}
+ */
 function getOptions() {
   if (
     process.argv.length === 3 &&
@@ -26,17 +71,11 @@ function getOptions() {
 
   const optsPath =
     process.argv.indexOf('--opts') === -1
-      ? 'test/mocha.opts'
+      ? defaultPathname
       : process.argv[process.argv.indexOf('--opts') + 1];
 
   try {
-    const opts = fs
-      .readFileSync(optsPath, 'utf8')
-      .replace(/^#.*$/gm, '')
-      .replace(/\\\s/g, '%20')
-      .split(/\s/)
-      .filter(Boolean)
-      .map(value => value.replace(/%20/g, ' '));
+    const opts = parseOptions(readOptionsFile(optsPath));
 
     process.argv = process.argv
       .slice(0, 2)
diff --git a/docs/index.md b/docs/index.md
index 066ee691ae..67376c4a35 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -780,73 +780,71 @@ Mocha supports the `err.expected` and `err.actual` properties of any thrown `Ass
 
 ## Usage
 
-```text
-  Usage: mocha [debug] [options] [files]
-
-  Options:
-
-    -V, --version                           output the version number
-    -A, --async-only                        force all tests to take a callback (async) or return a promise
-    -c, --colors                            force enabling of colors
-    -C, --no-colors                         force disabling of colors
-    -G, --growl                             enable Growl notification support
-    -O, --reporter-options <k=v,k2=v2,...>  reporter-specific options
-    -R, --reporter <name>                   specify the reporter to use (default: spec)
-    -S, --sort                              sort test files
-    -b, --bail                              bail after first test failure
-    -d, --debug                             enable node's debugger, synonym for node --debug
-    -g, --grep <pattern>                    only run tests matching <pattern>
-    -f, --fgrep <string>                    only run tests containing <string>
-    -gc, --expose-gc                        expose gc extension
-    -i, --invert                            inverts --grep and --fgrep matches
-    -r, --require <name>                    require the given module
-    -s, --slow <ms>                         "slow" test threshold in milliseconds [75]
-    -t, --timeout <ms>                      set test-case timeout in milliseconds [2000]
-    -u, --ui <name>                         specify user-interface (bdd|tdd|qunit|exports) (default: bdd)
-    -w, --watch                             watch files in the current working directory for changes
-    --check-leaks                           check for global variable leaks
-    --full-trace                            display the full stack trace
-    --compilers <ext>:<module>,...          use the given module(s) to compile files (default: )
-    --debug-brk                             enable node's debugger breaking on the first line
-    --globals <names>                       allow the given comma-delimited global [names] (default: )
-    --es_staging                            enable all staged features
-    --harmony<_classes,_generators,...>     all node --harmony* flags are available
-    --preserve-symlinks                     Instructs the module loader to preserve symbolic links when resolving and caching modules
-    --icu-data-dir                          include ICU data
-    --inline-diffs                          display actual/expected differences inline within each string
-    --no-diff                               do not show a diff on failure
-    --inspect                               activate devtools in chrome
-    --inspect-brk                           activate devtools in chrome and break on the first line
-    --interfaces                            display available interfaces
-    --no-deprecation                        silence deprecation warnings
-    --exit                                  force shutdown of the event loop after test run: mocha will call process.exit
-    --no-timeouts                           disables timeouts, given implicitly with --debug
-    --no-warnings                           silence all node process warnings
-    --opts <path>                           specify opts path (default: test/mocha.opts)
-    --perf-basic-prof                       enable perf linux profiler (basic support)
-    --napi-modules                          enable experimental NAPI modules
-    --prof                                  log statistical profiling information
-    --log-timer-events                      Time events including external callbacks
-    --recursive                             include sub directories
-    --reporters                             display available reporters
-    --retries <times>                       set numbers of time to retry a failed test case
-    --throw-deprecation                     throw an exception anytime a deprecated function is used
-    --trace                                 trace function calls
-    --trace-deprecation                     show stack traces on deprecations
-    --trace-warnings                        show stack traces on node process warnings
-    --use_strict                            enforce strict mode
-    --watch-extensions <ext>,...            specify extensions to monitor with --watch (default: js)
-    --delay                                 wait for async suite definition
-    --allow-uncaught                        enable uncaught errors to propagate
-    --forbid-only                           causes test marked with only to fail the suite
-    --forbid-pending                        causes pending tests and test marked with skip to fail the suite
-    --file <file>                           include a file to be ran during the suite (default: )
-    --exclude <file>                        a file or glob pattern to ignore (default: )
-    -h, --help                              output usage information
-
-  Commands:
-
-    init <path>  initialize a client-side mocha setup at <path>
+```console
+Usage: mocha [debug] [options] [files]
+
+Options:
+  -V, --version                           output the version number
+  -A, --async-only                        force all tests to take a callback (async) or return a promise
+  -c, --colors                            force enabling of colors
+  -C, --no-colors                         force disabling of colors
+  -G, --growl                             enable growl notification support
+  -O, --reporter-options <k=v,k2=v2,...>  reporter-specific options
+  -R, --reporter <name>                   specify the reporter to use (default: "spec")
+  -S, --sort                              sort test files
+  -b, --bail                              bail after first test failure
+  -d, --debug                             enable node's debugger, synonym for node --debug
+  -g, --grep <pattern>                    only run tests matching <pattern>
+  -f, --fgrep <string>                    only run tests containing <string>
+  -gc, --expose-gc                        expose gc extension
+  -i, --invert                            inverts --grep and --fgrep matches
+  -r, --require <name>                    require the given module (default: [])
+  -s, --slow <ms>                         specify "slow" test threshold in milliseconds (default: 75)
+  -t, --timeout <ms>                      specify test timeout threshold in milliseconds (default: 2000)
+  -u, --ui <name>                         specify user-interface (bdd|tdd|qunit|exports) (default: "bdd")
+  -w, --watch                             watch files in the current working directory for changes
+  --check-leaks                           check for global variable leaks
+  --full-trace                            display the full stack trace
+  --compilers <ext>:<module>,...          use the given module(s) to compile files (default: [])
+  --debug-brk                             enable node's debugger breaking on the first line
+  --globals <names>                       allow the given comma-delimited global [names] (default: [])
+  --es_staging                            enable all staged features
+  --harmony<_classes,_generators,...>     all node --harmony* flags are available
+  --preserve-symlinks                     Instructs the module loader to preserve symbolic links when resolving and caching modules
+  --icu-data-dir                          include ICU data
+  --inline-diffs                          display actual/expected differences inline within each string
+  --no-diff                               do not show a diff on failure
+  --inspect                               activate devtools in chrome
+  --inspect-brk                           activate devtools in chrome and break on the first line
+  --interfaces                            output provided interfaces and exit
+  --no-deprecation                        silence deprecation warnings
+  --exit                                  force shutdown of the event loop after test run: mocha will call process.exit
+  --no-timeouts                           disables timeouts, given implicitly with --debug/--inspect
+  --no-warnings                           silence all node process warnings
+  --opts <path>                           specify opts path (default: "test/mocha.opts")
+  --perf-basic-prof                       enable perf linux profiler (basic support)
+  --napi-modules                          enable experimental NAPI modules
+  --prof                                  log statistical profiling information
+  --log-timer-events                      Time events including external callbacks
+  --recursive                             include sub directories
+  --reporters                             output provided reporters and exit
+  --retries <times>                       specify number of times to retry a failed test case (default: 0)
+  --throw-deprecation                     throw an exception anytime a deprecated function is used
+  --trace                                 trace function calls
+  --trace-deprecation                     show stack traces on deprecations
+  --trace-warnings                        show stack traces on node process warnings
+  --use_strict                            enforce strict mode
+  --watch-extensions <ext>,...            specify extensions to monitor with --watch (default: ["js"])
+  --delay                                 wait for async suite definition
+  --allow-uncaught                        enable uncaught errors to propagate
+  --forbid-only                           causes test marked with only to fail the suite
+  --forbid-pending                        causes pending tests and test marked with skip to fail the suite
+  --file <file>                           adds file be loaded prior to suite execution (default: [])
+  --exclude <file>                        adds file or glob pattern to ignore (default: [])
+  -h, --help                              output usage information
+
+Commands:
+  init <path>                             initialize a client-side mocha setup at <path>
 ```
 
 ### `-w, --watch`
diff --git a/lib/interfaces/common.js b/lib/interfaces/common.js
index 4ca340a608..7997312786 100644
--- a/lib/interfaces/common.js
+++ b/lib/interfaces/common.js
@@ -1,6 +1,7 @@
 'use strict';
 
 var Suite = require('../suite');
+var utils = require('../utils');
 
 /**
  * Functions common to more than one interface.
@@ -92,6 +93,7 @@ module.exports = function(suites, context, mocha) {
 
       /**
        * Creates a suite.
+       *
        * @param {Object} opts Options
        * @param {string} opts.title Title of Suite
        * @param {Function} [opts.fn] Suite Function (not always applicable)
@@ -109,13 +111,22 @@ module.exports = function(suites, context, mocha) {
           suite.parent._onlySuites = suite.parent._onlySuites.concat(suite);
         }
         if (typeof opts.fn === 'function') {
-          opts.fn.call(suite);
+          var result = opts.fn.call(suite);
+          if (typeof result !== 'undefined') {
+            utils.deprecate(
+              'Deprecation Warning: Suites do not support a return value;' +
+                opts.title +
+                ' returned :' +
+                result
+            );
+          }
           suites.shift();
         } else if (typeof opts.fn === 'undefined' && !suite.pending) {
           throw new Error(
             'Suite "' +
               suite.fullTitle() +
-              '" was defined but no callback was supplied. Supply a callback or explicitly skip the suite.'
+              '" was defined but no callback was supplied. ' +
+              'Supply a callback or explicitly skip the suite.'
           );
         } else if (!opts.fn && suite.pending) {
           suites.shift();
diff --git a/lib/mocha.js b/lib/mocha.js
index dabea27e00..3fd8d6cafa 100644
--- a/lib/mocha.js
+++ b/lib/mocha.js
@@ -675,6 +675,20 @@ Mocha.prototype.forbidPending = function() {
   return this;
 };
 
+/**
+ * Mocha version as specified by "package.json".
+ *
+ * @name Mocha#version
+ * @type string
+ * @readonly
+ */
+Object.defineProperty(Mocha.prototype, 'version', {
+  value: require('../package').version,
+  configurable: false,
+  enumerable: true,
+  writable: false
+});
+
 /**
  * Callback to be invoked when test execution is complete.
  *
diff --git a/lib/reporters/json-stream.js b/lib/reporters/json-stream.js
index 0edd0cbf88..5b4cfbcebe 100644
--- a/lib/reporters/json-stream.js
+++ b/lib/reporters/json-stream.js
@@ -9,55 +9,68 @@
 var Base = require('./base');
 
 /**
- * Expose `List`.
+ * Expose `JSONStream`.
  */
 
-exports = module.exports = List;
+exports = module.exports = JSONStream;
 
 /**
- * Initialize a new `JSONStream` test reporter.
+ * Constructs a new `JSONStream` reporter instance.
  *
  * @public
- * @name JSONStream
- * @class JSONStream
- * @memberof Mocha.reporters
+ * @class
  * @extends Mocha.reporters.Base
- * @api public
- * @param {Runner} runner
+ * @memberof Mocha.reporters
+ * @param {Runner} runner - Instance triggers reporter actions.
  */
-function List(runner) {
+function JSONStream(runner) {
   Base.call(this, runner);
 
   var self = this;
   var total = runner.total;
 
-  runner.on('start', function() {
-    console.log(JSON.stringify(['start', {total: total}]));
+  runner.once('start', function() {
+    writeEvent(['start', {total: total}]);
   });
 
   runner.on('pass', function(test) {
-    console.log(JSON.stringify(['pass', clean(test)]));
+    writeEvent(['pass', clean(test)]);
   });
 
   runner.on('fail', function(test, err) {
     test = clean(test);
     test.err = err.message;
     test.stack = err.stack || null;
-    console.log(JSON.stringify(['fail', test]));
+    writeEvent(['fail', test]);
   });
 
   runner.once('end', function() {
-    process.stdout.write(JSON.stringify(['end', self.stats]));
+    writeEvent(['end', self.stats]);
   });
 }
 
 /**
- * Return a plain-object representation of `test`
- * free of cyclic properties etc.
+ * Mocha event to be written to the output stream.
+ * @typedef {Array} JSONStream~MochaEvent
+ */
+
+/**
+ * Writes Mocha event to reporter output stream.
+ *
+ * @private
+ * @param {JSONStream~MochaEvent} event - Mocha event to be output.
+ */
+function writeEvent(event) {
+  process.stdout.write(JSON.stringify(event) + '\n');
+}
+
+/**
+ * Returns an object literal representation of `test`
+ * free of cyclic properties, etc.
  *
- * @api private
- * @param {Object} test
- * @return {Object}
+ * @private
+ * @param {Test} test - Instance used as data source.
+ * @return {Object} object containing pared-down test instance data
  */
 function clean(test) {
   return {
diff --git a/lib/reporters/tap.js b/lib/reporters/tap.js
index feaf7ea21a..ccff657e6a 100644
--- a/lib/reporters/tap.js
+++ b/lib/reporters/tap.js
@@ -6,7 +6,10 @@
  * Module dependencies.
  */
 
+var util = require('util');
 var Base = require('./base');
+var inherits = require('../utils').inherits;
+var sprintf = util.format;
 
 /**
  * Expose `TAP`.
@@ -15,25 +18,34 @@ var Base = require('./base');
 exports = module.exports = TAP;
 
 /**
- * Initialize a new `TAP` reporter.
+ * Constructs a new TAP reporter with runner instance and reporter options.
  *
  * @public
  * @class
- * @memberof Mocha.reporters
  * @extends Mocha.reporters.Base
- * @api public
- * @param {Runner} runner
+ * @memberof Mocha.reporters
+ * @param {Runner} runner - Instance triggers reporter actions.
+ * @param {Object} [options] - runner options
  */
-function TAP(runner) {
-  Base.call(this, runner);
+function TAP(runner, options) {
+  Base.call(this, runner, options);
 
+  var self = this;
   var n = 1;
-  var passes = 0;
-  var failures = 0;
 
-  runner.on('start', function() {
-    var total = runner.grepTotal(runner.suite);
-    console.log('%d..%d', 1, total);
+  var tapVersion = '12';
+  if (options && options.reporterOptions) {
+    if (options.reporterOptions.tapVersion) {
+      tapVersion = options.reporterOptions.tapVersion.toString();
+    }
+  }
+
+  this._producer = createProducer(tapVersion);
+
+  runner.once('start', function() {
+    var ntests = runner.grepTotal(runner.suite);
+    self._producer.writeVersion();
+    self._producer.writePlan(ntests);
   });
 
   runner.on('test end', function() {
@@ -41,39 +53,233 @@ function TAP(runner) {
   });
 
   runner.on('pending', function(test) {
-    console.log('ok %d %s # SKIP -', n, title(test));
+    self._producer.writePending(n, test);
   });
 
   runner.on('pass', function(test) {
-    passes++;
-    console.log('ok %d %s', n, title(test));
+    self._producer.writePass(n, test);
   });
 
   runner.on('fail', function(test, err) {
-    failures++;
-    console.log('not ok %d %s', n, title(test));
-    if (err.message) {
-      console.log(err.message.replace(/^/gm, '  '));
-    }
-    if (err.stack) {
-      console.log(err.stack.replace(/^/gm, '  '));
-    }
+    self._producer.writeFail(n, test, err);
   });
 
   runner.once('end', function() {
-    console.log('# tests ' + (passes + failures));
-    console.log('# pass ' + passes);
-    console.log('# fail ' + failures);
+    self._producer.writeEpilogue(runner.stats);
   });
 }
 
 /**
- * Return a TAP-safe title of `test`
+ * Inherit from `Base.prototype`.
+ */
+inherits(TAP, Base);
+
+/**
+ * Returns a TAP-safe title of `test`.
  *
- * @api private
- * @param {Object} test
- * @return {String}
+ * @private
+ * @param {Test} test - Test instance.
+ * @return {String} title with any hash character removed
  */
 function title(test) {
   return test.fullTitle().replace(/#/g, '');
 }
+
+/**
+ * Writes newline-terminated formatted string to reporter output stream.
+ *
+ * @private
+ * @param {string} format - `printf`-like format string
+ * @param {...*} [varArgs] - Format string arguments
+ */
+function println(format, varArgs) {
+  var vargs = Array.from(arguments);
+  vargs[0] += '\n';
+  process.stdout.write(sprintf.apply(null, vargs));
+}
+
+/**
+ * Returns a `tapVersion`-appropriate TAP producer instance, if possible.
+ *
+ * @private
+ * @param {string} tapVersion - Version of TAP specification to produce.
+ * @returns {TAPProducer} specification-appropriate instance
+ * @throws {Error} if specification version has no associated producer.
+ */
+function createProducer(tapVersion) {
+  var producers = {
+    '12': new TAP12Producer(),
+    '13': new TAP13Producer()
+  };
+  var producer = producers[tapVersion];
+
+  if (!producer) {
+    throw new Error(
+      'invalid or unsupported TAP version: ' + JSON.stringify(tapVersion)
+    );
+  }
+
+  return producer;
+}
+
+/**
+ * @summary
+ * Constructs a new TAPProducer.
+ *
+ * @description
+ * <em>Only</em> to be used as an abstract base class.
+ *
+ * @private
+ * @constructor
+ */
+function TAPProducer() {}
+
+/**
+ * Writes the TAP version to reporter output stream.
+ *
+ * @abstract
+ */
+TAPProducer.prototype.writeVersion = function() {};
+
+/**
+ * Writes the plan to reporter output stream.
+ *
+ * @abstract
+ * @param {number} ntests - Number of tests that are planned to run.
+ */
+TAPProducer.prototype.writePlan = function(ntests) {
+  println('%d..%d', 1, ntests);
+};
+
+/**
+ * Writes that test passed to reporter output stream.
+ *
+ * @abstract
+ * @param {number} n - Index of test that passed.
+ * @param {Test} test - Instance containing test information.
+ */
+TAPProducer.prototype.writePass = function(n, test) {
+  println('ok %d %s', n, title(test));
+};
+
+/**
+ * Writes that test was skipped to reporter output stream.
+ *
+ * @abstract
+ * @param {number} n - Index of test that was skipped.
+ * @param {Test} test - Instance containing test information.
+ */
+TAPProducer.prototype.writePending = function(n, test) {
+  println('ok %d %s # SKIP -', n, title(test));
+};
+
+/**
+ * Writes that test failed to reporter output stream.
+ *
+ * @abstract
+ * @param {number} n - Index of test that failed.
+ * @param {Test} test - Instance containing test information.
+ * @param {Error} err - Reason the test failed.
+ */
+TAPProducer.prototype.writeFail = function(n, test, err) {
+  println('not ok %d %s', n, title(test));
+};
+
+/**
+ * Writes the summary epilogue to reporter output stream.
+ *
+ * @abstract
+ * @param {Object} stats - Object containing run statistics.
+ */
+TAPProducer.prototype.writeEpilogue = function(stats) {
+  // :TBD: Why is this not counting pending tests?
+  println('# tests ' + (stats.passes + stats.failures));
+  println('# pass ' + stats.passes);
+  // :TBD: Why are we not showing pending results?
+  println('# fail ' + stats.failures);
+};
+
+/**
+ * @summary
+ * Constructs a new TAP12Producer.
+ *
+ * @description
+ * Produces output conforming to the TAP12 specification.
+ *
+ * @private
+ * @constructor
+ * @extends TAPProducer
+ * @see {@link https://testanything.org/tap-specification.html|Specification}
+ */
+function TAP12Producer() {
+  /**
+   * Writes that test failed to reporter output stream, with error formatting.
+   * @override
+   */
+  this.writeFail = function(n, test, err) {
+    TAPProducer.prototype.writeFail.call(this, n, test, err);
+    if (err.message) {
+      println(err.message.replace(/^/gm, '  '));
+    }
+    if (err.stack) {
+      println(err.stack.replace(/^/gm, '  '));
+    }
+  };
+}
+
+/**
+ * Inherit from `TAPProducer.prototype`.
+ */
+inherits(TAP12Producer, TAPProducer);
+
+/**
+ * @summary
+ * Constructs a new TAP13Producer.
+ *
+ * @description
+ * Produces output conforming to the TAP13 specification.
+ *
+ * @private
+ * @constructor
+ * @extends TAPProducer
+ * @see {@link https://testanything.org/tap-version-13-specification.html|Specification}
+ */
+function TAP13Producer() {
+  /**
+   * Writes the TAP version to reporter output stream.
+   * @override
+   */
+  this.writeVersion = function() {
+    println('TAP version 13');
+  };
+
+  /**
+   * Writes that test failed to reporter output stream, with error formatting.
+   * @override
+   */
+  this.writeFail = function(n, test, err) {
+    TAPProducer.prototype.writeFail.call(this, n, test, err);
+    var emitYamlBlock = err.message != null || err.stack != null;
+    if (emitYamlBlock) {
+      println(indent(1) + '---');
+      if (err.message) {
+        println(indent(2) + 'message: |-');
+        println(err.message.replace(/^/gm, indent(3)));
+      }
+      if (err.stack) {
+        println(indent(2) + 'stack: |-');
+        println(err.stack.replace(/^/gm, indent(3)));
+      }
+      println(indent(1) + '...');
+    }
+  };
+
+  function indent(level) {
+    return Array(level + 1).join('  ');
+  }
+}
+
+/**
+ * Inherit from `TAPProducer.prototype`.
+ */
+inherits(TAP13Producer, TAPProducer);
diff --git a/lib/reporters/xunit.js b/lib/reporters/xunit.js
index c1a930d2d8..bd89a37e76 100644
--- a/lib/reporters/xunit.js
+++ b/lib/reporters/xunit.js
@@ -151,6 +151,8 @@ XUnit.prototype.write = function(line) {
  * @param {Test} test
  */
 XUnit.prototype.test = function(test) {
+  Base.useColors = false;
+
   var attrs = {
     classname: test.parent.fullTitle(),
     name: test.title,
@@ -159,6 +161,10 @@ XUnit.prototype.test = function(test) {
 
   if (test.state === 'failed') {
     var err = test.err;
+    var diff =
+      Base.hideDiff || !err.actual || !err.expected
+        ? ''
+        : '\n' + Base.generateDiff(err.actual, err.expected);
     this.write(
       tag(
         'testcase',
@@ -168,7 +174,7 @@ XUnit.prototype.test = function(test) {
           'failure',
           {},
           false,
-          escape(err.message) + '\n' + escape(err.stack)
+          escape(err.message) + escape(diff) + '\n' + escape(err.stack)
         )
       )
     );
diff --git a/lib/runnable.js b/lib/runnable.js
index 73da817793..2e62a6bc8b 100644
--- a/lib/runnable.js
+++ b/lib/runnable.js
@@ -50,23 +50,43 @@ function Runnable(title, fn) {
 utils.inherits(Runnable, EventEmitter);
 
 /**
- * Set & get timeout `ms`.
+ * Get current timeout value in msecs.
  *
- * @api private
- * @param {number|string} ms
- * @return {Runnable|number} ms or Runnable instance.
+ * @private
+ * @returns {number} current timeout threshold value
+ */
+/**
+ * @summary
+ * Set timeout threshold value (msecs).
+ *
+ * @description
+ * A string argument can use shorthand (e.g., "2s") and will be converted.
+ * The value will be clamped to range [<code>0</code>, <code>2^<sup>31</sup>-1</code>].
+ * If clamped value matches either range endpoint, timeouts will be disabled.
+ *
+ * @private
+ * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/setTimeout#Maximum_delay_value}
+ * @param {number|string} ms - Timeout threshold value.
+ * @returns {Runnable} this
+ * @chainable
  */
 Runnable.prototype.timeout = function(ms) {
   if (!arguments.length) {
     return this._timeout;
   }
-  // see #1652 for reasoning
-  if (ms === 0 || ms > Math.pow(2, 31)) {
-    this._enableTimeouts = false;
-  }
   if (typeof ms === 'string') {
     ms = milliseconds(ms);
   }
+
+  // Clamp to range
+  var INT_MAX = Math.pow(2, 31) - 1;
+  var range = [0, INT_MAX];
+  ms = utils.clamp(ms, range);
+
+  // see #1652 for reasoning
+  if (ms === range[0] || ms === range[1]) {
+    this._enableTimeouts = false;
+  }
   debug('timeout %d', ms);
   this._timeout = ms;
   if (this.timer) {
diff --git a/lib/runner.js b/lib/runner.js
index d105bca321..dc2092f9fa 100644
--- a/lib/runner.js
+++ b/lib/runner.js
@@ -851,10 +851,15 @@ Runner.prototype.run = function(fn) {
       filterOnly(rootSuite);
     }
     self.started = true;
-    self.emit('start');
+    Runner.immediately(function() {
+      self.emit('start');
+    });
+
     self.runSuite(rootSuite, function() {
       debug('finished running');
-      self.emit('end');
+      Runner.immediately(function() {
+        self.emit('end');
+      });
     });
   }
 
diff --git a/lib/utils.js b/lib/utils.js
index e67bf74414..6e78a99b71 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -584,6 +584,34 @@ exports.getError = function(err) {
   return err || exports.undefinedError();
 };
 
+/**
+ * Show a deprecation warning. Each distinct message is only displayed once.
+ *
+ * @param {string} msg
+ */
+exports.deprecate = function(msg) {
+  msg = String(msg);
+  if (seenDeprecationMsg.hasOwnProperty(msg)) {
+    return;
+  }
+  seenDeprecationMsg[msg] = true;
+  doDeprecationWarning(msg);
+};
+
+var seenDeprecationMsg = {};
+
+var doDeprecationWarning = process.emitWarning
+  ? function(msg) {
+      // Node.js v6+
+      process.emitWarning(msg, 'DeprecationWarning');
+    }
+  : function(msg) {
+      // Everything else
+      process.nextTick(function() {
+        console.warn(msg);
+      });
+    };
+
 /**
  * @summary
  * This Filter based on `mocha-clean` module.(see: `github.com/rstacruz/mocha-clean`)
@@ -663,6 +691,17 @@ exports.isPromise = function isPromise(value) {
   return typeof value === 'object' && typeof value.then === 'function';
 };
 
+/**
+ * Clamps a numeric value to an inclusive range.
+ *
+ * @param {number} value - Value to be clamped.
+ * @param {numer[]} range - Two element array specifying [min, max] range.
+ * @returns {number} clamped value
+ */
+exports.clamp = function clamp(value, range) {
+  return Math.min(Math.max(value, range[0]), range[1]);
+};
+
 /**
  * It's a noop.
  * @api
diff --git a/package-lock.json b/package-lock.json
index 782bb42830..72c4a6f2ec 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1316,6 +1316,12 @@
         "inherits": "^2.0.1"
       }
     },
+    "browserify-package-json": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/browserify-package-json/-/browserify-package-json-1.0.1.tgz",
+      "integrity": "sha1-mN3oqlxWH9bT/km7qhArdLOW/eo=",
+      "dev": true
+    },
     "browserify-rsa": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/browserify-rsa/-/browserify-rsa-4.0.1.tgz",
@@ -2026,9 +2032,9 @@
       }
     },
     "commander": {
-      "version": "2.15.1",
-      "resolved": "https://registry.npmjs.org/commander/-/commander-2.15.1.tgz",
-      "integrity": "sha512-VlfT9F3V0v+jr4yxPc5gg9s62/fIVWsd2Bk2iD435um1NlGMYdVCq+MjcXnhYq2icNOizHr1kK+5TI6H0Hy0ag=="
+      "version": "2.19.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-2.19.0.tgz",
+      "integrity": "sha512-6tvAOO+D6OENvRAh524Dh9jcfKTYDQAqvqezbCW82xj5X0pSrcpxtvRKHLG0yBY6SD7PSDrJaj+0AiOcKVd1Xg=="
     },
     "comment-regex": {
       "version": "1.0.1",
@@ -5939,6 +5945,12 @@
         "uglify-js": "3.3.x"
       },
       "dependencies": {
+        "commander": {
+          "version": "2.15.1",
+          "resolved": "http://registry.npmjs.org/commander/-/commander-2.15.1.tgz",
+          "integrity": "sha512-VlfT9F3V0v+jr4yxPc5gg9s62/fIVWsd2Bk2iD435um1NlGMYdVCq+MjcXnhYq2icNOizHr1kK+5TI6H0Hy0ag==",
+          "dev": true
+        },
         "source-map": {
           "version": "0.6.1",
           "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
@@ -13680,6 +13692,15 @@
         "thunkify": "^2.1.2"
       }
     },
+    "package-json-versionify": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/package-json-versionify/-/package-json-versionify-1.0.4.tgz",
+      "integrity": "sha1-WGBYepRIc6a35tJujlH/siMVvxc=",
+      "dev": true,
+      "requires": {
+        "browserify-package-json": "^1.0.0"
+      }
+    },
     "pako": {
       "version": "1.0.6",
       "resolved": "https://registry.npmjs.org/pako/-/pako-1.0.6.tgz",
@@ -17954,6 +17975,12 @@
         "source-map": "~0.6.1"
       },
       "dependencies": {
+        "commander": {
+          "version": "2.15.1",
+          "resolved": "http://registry.npmjs.org/commander/-/commander-2.15.1.tgz",
+          "integrity": "sha512-VlfT9F3V0v+jr4yxPc5gg9s62/fIVWsd2Bk2iD435um1NlGMYdVCq+MjcXnhYq2icNOizHr1kK+5TI6H0Hy0ag==",
+          "dev": true
+        },
         "source-map": {
           "version": "0.6.1",
           "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
diff --git a/package.json b/package.json
index 002b55e32b..7b1938ffa1 100644
--- a/package.json
+++ b/package.json
@@ -446,10 +446,19 @@
     "type": "git",
     "url": "https://github.com/mochajs/mocha.git"
   },
+  "bugs": {
+    "url": "https://github.com/mochajs/mocha/issues/"
+  },
+  "homepage": "https://mochajs.org/",
+  "logo": "https://cldup.com/S9uQ-cOLYz.svg",
   "bin": {
     "mocha": "./bin/mocha",
     "_mocha": "./bin/_mocha"
   },
+  "directories": {
+    "lib": "./lib",
+    "test": "./test"
+  },
   "engines": {
     "node": ">= 6.0.0"
   },
@@ -461,7 +470,7 @@
   },
   "dependencies": {
     "browser-stdout": "1.3.1",
-    "commander": "2.15.1",
+    "commander": "2.19.0",
     "debug": "3.1.0",
     "diff": "3.5.0",
     "escape-string-regexp": "1.0.5",
@@ -502,6 +511,7 @@
     "markdownlint-cli": "^0.9.0",
     "nps": "^5.7.1",
     "nyc": "^11.7.3",
+    "package-json-versionify": "^1.0.4",
     "prettier-eslint-cli": "^4.7.1",
     "rimraf": "^2.5.2",
     "svgo": "^0.7.2",
@@ -510,14 +520,19 @@
     "watchify": "^3.7.0"
   },
   "files": [
-    "bin",
-    "images",
-    "lib",
+    "bin/{*mocha,options.js}",
+    "assets/growl/*.png",
+    "lib/**/*.{js,html}",
     "index.js",
     "mocha.css",
     "mocha.js",
     "browser-entry.js"
   ],
+  "browserify": {
+    "transform": [
+      "package-json-versionify"
+    ]
+  },
   "browser": {
     "growl": "./lib/browser/growl.js",
     "tty": "./lib/browser/tty.js",
@@ -527,8 +542,6 @@
     "path": false,
     "supports-color": false
   },
-  "homepage": "https://mochajs.org",
-  "logo": "https://cldup.com/S9uQ-cOLYz.svg",
   "prettier": {
     "singleQuote": true,
     "bracketSpacing": false
diff --git a/test/integration/deprecate.spec.js b/test/integration/deprecate.spec.js
new file mode 100644
index 0000000000..db806fcde5
--- /dev/null
+++ b/test/integration/deprecate.spec.js
@@ -0,0 +1,18 @@
+'use strict';
+
+var assert = require('assert');
+var run = require('./helpers').runMocha;
+var args = [];
+
+describe('utils.deprecate test', function() {
+  it('should print unique deprecation only once', function(done) {
+    run('deprecate.fixture.js', args, function(err, res) {
+      if (err) {
+        return done(err);
+      }
+      var result = res.output.match(/deprecated thing/g) || [];
+      assert.equal(result.length, 2);
+      done();
+    });
+  });
+});
diff --git a/test/integration/fixtures/deprecate.fixture.js b/test/integration/fixtures/deprecate.fixture.js
new file mode 100644
index 0000000000..cf98884600
--- /dev/null
+++ b/test/integration/fixtures/deprecate.fixture.js
@@ -0,0 +1,9 @@
+'use strict';
+
+var utils = require("../../../lib/utils");
+
+it('consolidates identical calls to deprecate', function() {
+  utils.deprecate("suite foo did a deprecated thing");
+  utils.deprecate("suite foo did a deprecated thing");
+  utils.deprecate("suite bar did a deprecated thing");
+});
diff --git a/test/integration/fixtures/reporters.fixture.js b/test/integration/fixtures/reporters.fixture.js
new file mode 100644
index 0000000000..ab16bc0eed
--- /dev/null
+++ b/test/integration/fixtures/reporters.fixture.js
@@ -0,0 +1,63 @@
+'use strict';
+
+/**
+ * This file generates a wide range of output to test reporter functionality.
+ */
+
+describe('Animals', function() {
+
+  it('should consume organic material', function(done) { done(); });
+  it('should breathe oxygen', function(done) {
+    // we're a jellyfish
+    var actualBreathe = 'nothing';
+    var expectedBreathe = 'oxygen';
+    expect(actualBreathe, 'to equal', expectedBreathe);
+    done();
+  });
+  it('should be able to move', function(done) { done(); });
+  it('should reproduce sexually', function(done) { done(); });
+  it('should grow from a hollow sphere of cells', function(done) { done(); });
+
+  describe('Vertebrates', function() {
+    describe('Mammals', function() {
+      it('should give birth to live young', function(done) {
+        var expectedMammal = {
+          consumesMaterial: 'organic',
+          breathe: 'oxygen',
+          reproduction: {
+            type: 'sexually',
+            spawnType: 'live',
+          }
+        };
+        var platypus = JSON.parse(JSON.stringify(expectedMammal));
+        platypus['reproduction']['spawnType'] = 'hard-shelled egg';
+
+        expect(platypus, 'to equal', expectedMammal);
+        done();
+      });
+
+      describe('Blue Whale', function() {
+        it('should be the largest of all mammals', function(done) { done(); });
+        it('should have a body in some shade of blue', function(done) {
+          var bodyColor = 'blueish_grey';
+          var shadesOfBlue = ['cyan', 'light_blue', 'blue', 'indigo'];
+          expect(bodyColor, 'to be one of', shadesOfBlue);
+
+          done();
+        });
+      });
+    });
+    describe('Birds', function() {
+      it('should have feathers', function(done) { done(); });
+      it('should lay hard-shelled eggs', function(done) { done(); });
+    });
+  });
+
+  describe('Tardigrades', function() {
+    it('should answer to "water bear"', function(done) { done(); });
+    it('should be able to survive global mass extinction events', function(done) {
+      throw new Error("How do we even test for this without causing one?")
+      done();
+    });
+  });
+});
diff --git a/test/integration/fixtures/suite/suite-returning-value.fixture.js b/test/integration/fixtures/suite/suite-returning-value.fixture.js
new file mode 100644
index 0000000000..8859cfb5d9
--- /dev/null
+++ b/test/integration/fixtures/suite/suite-returning-value.fixture.js
@@ -0,0 +1,5 @@
+'use strict';
+
+describe('a suite returning a value', function () {
+  return Promise.resolve();
+});
diff --git a/test/integration/reporters.spec.js b/test/integration/reporters.spec.js
index 4e95622dee..c78da8ab6b 100644
--- a/test/integration/reporters.spec.js
+++ b/test/integration/reporters.spec.js
@@ -99,4 +99,137 @@ describe('reporters', function() {
       });
     });
   });
+
+  describe('tap', function() {
+    var not = function(predicate) {
+      return function() {
+        return !predicate.apply(this, arguments);
+      };
+    };
+    var versionPredicate = function(line) {
+      return line.match(/^TAP version \d+$/) != null;
+    };
+    var planPredicate = function(line) {
+      return line.match(/^1\.\.\d+$/) != null;
+    };
+    var testLinePredicate = function(line) {
+      return line.match(/^not ok/) != null || line.match(/^ok/) != null;
+    };
+    var diagnosticPredicate = function(line) {
+      return line.match(/^#/) != null;
+    };
+    var bailOutPredicate = function(line) {
+      return line.match(/^Bail out!/) != null;
+    };
+    var anythingElsePredicate = function(line) {
+      return (
+        versionPredicate(line) === false &&
+        planPredicate(line) === false &&
+        testLinePredicate(line) === false &&
+        diagnosticPredicate(line) === false &&
+        bailOutPredicate(line) === false
+      );
+    };
+
+    describe('produces valid TAP v13 output', function() {
+      var runFixtureAndValidateOutput = function(fixture, expected) {
+        it('for ' + fixture, function(done) {
+          var args = ['--reporter=tap', '--reporter-options', 'tapVersion=13'];
+
+          run(fixture, args, function(err, res) {
+            if (err) {
+              done(err);
+              return;
+            }
+
+            var expectedVersion = 13;
+            var expectedPlan = '1..' + expected.numTests;
+
+            var outputLines = res.output.split('\n');
+
+            // first line must be version line
+            expect(
+              outputLines[0],
+              'to equal',
+              'TAP version ' + expectedVersion
+            );
+
+            // plan must appear once
+            expect(outputLines, 'to contain', expectedPlan);
+            expect(
+              outputLines.filter(function(l) {
+                return l === expectedPlan;
+              }),
+              'to have length',
+              1
+            );
+            // plan cannot appear in middle of the output
+            var firstTestLine = outputLines.findIndex(testLinePredicate);
+            // there must be at least one test line
+            expect(firstTestLine, 'to be greater than', -1);
+            var lastTestLine =
+              outputLines.length -
+              1 -
+              outputLines
+                .slice()
+                .reverse()
+                .findIndex(testLinePredicate);
+            var planLine = outputLines.findIndex(function(line) {
+              return line === expectedPlan;
+            });
+            expect(
+              planLine < firstTestLine || planLine > lastTestLine,
+              'to equal',
+              true
+            );
+
+            done();
+          });
+        });
+      };
+
+      runFixtureAndValidateOutput('passing.fixture.js', {
+        numTests: 2
+      });
+      runFixtureAndValidateOutput('reporters.fixture.js', {
+        numTests: 12
+      });
+    });
+
+    it('places exceptions correctly in YAML blocks', function(done) {
+      var args = ['--reporter=tap', '--reporter-options', 'tapVersion=13'];
+
+      run('reporters.fixture.js', args, function(err, res) {
+        if (err) {
+          done(err);
+          return;
+        }
+
+        var outputLines = res.output.split('\n');
+
+        for (var i = 0; i + 1 < outputLines.length; i++) {
+          if (
+            testLinePredicate(outputLines[i]) &&
+            testLinePredicate(outputLines[i + 1]) === false
+          ) {
+            var blockLinesStart = i + 1;
+            var blockLinesEnd =
+              i +
+              1 +
+              outputLines.slice(i + 1).findIndex(not(anythingElsePredicate));
+            var blockLines =
+              blockLinesEnd > blockLinesStart
+                ? outputLines.slice(blockLinesStart, blockLinesEnd)
+                : outputLines.slice(blockLinesStart);
+            i += blockLines.length;
+
+            expect(blockLines[0], 'to match', /^\s+---/);
+            expect(blockLines[blockLines.length - 1], 'to match', /^\s+\.\.\./);
+          }
+        }
+
+        done();
+      });
+    });
+  });
 });
diff --git a/test/integration/suite.spec.js b/test/integration/suite.spec.js
index e8bd34382b..338a198f63 100644
--- a/test/integration/suite.spec.js
+++ b/test/integration/suite.spec.js
@@ -9,8 +9,7 @@ describe('suite w/no callback', function() {
   it('should throw a helpful error message when a callback for suite is not supplied', function(done) {
     run('suite/suite-no-callback.fixture.js', args, function(err, res) {
       if (err) {
-        done(err);
-        return;
+        return done(err);
       }
       var result = res.output.match(/no callback was supplied/) || [];
       assert.equal(result.length, 1);
@@ -24,8 +23,7 @@ describe('skipped suite w/no callback', function() {
   it('should not throw an error when a callback for skipped suite is not supplied', function(done) {
     run('suite/suite-skipped-no-callback.fixture.js', args, function(err, res) {
       if (err) {
-        done(err);
-        return;
+        return done(err);
       }
       var pattern = new RegExp('Error', 'g');
       var result = res.output.match(pattern) || [];
@@ -40,8 +38,7 @@ describe('skipped suite w/ callback', function() {
   it('should not throw an error when a callback for skipped suite is supplied', function(done) {
     run('suite/suite-skipped-callback.fixture.js', args, function(err, res) {
       if (err) {
-        done(err);
-        return;
+        return done(err);
       }
       var pattern = new RegExp('Error', 'g');
       var result = res.output.match(pattern) || [];
@@ -50,3 +47,18 @@ describe('skipped suite w/ callback', function() {
     });
   });
 });
+
+describe('suite returning a value', function() {
+  this.timeout(2000);
+  it('should give a deprecation warning for suite callback returning a value', function(done) {
+    run('suite/suite-returning-value.fixture.js', args, function(err, res) {
+      if (err) {
+        return done(err);
+      }
+      var pattern = new RegExp('Deprecation Warning', 'g');
+      var result = res.output.match(pattern) || [];
+      assert.equal(result.length, 1);
+      done();
+    });
+  });
+});
diff --git a/test/reporters/base.spec.js b/test/reporters/base.spec.js
index 8ff2195f70..f880b7b240 100644
--- a/test/reporters/base.spec.js
+++ b/test/reporters/base.spec.js
@@ -312,6 +312,7 @@ describe('Base reporter', function() {
   });
 
   it('should interpret Chai custom error messages', function() {
+    this.timeout(1000);
     var chaiExpect = require('chai').expect;
     try {
       chaiExpect(43, 'custom error message').to.equal(42);
diff --git a/test/reporters/doc.spec.js b/test/reporters/doc.spec.js
index e3de653528..857922b83e 100644
--- a/test/reporters/doc.spec.js
+++ b/test/reporters/doc.spec.js
@@ -4,22 +4,15 @@ var reporters = require('../../').reporters;
 var Doc = reporters.Doc;
 
 var createMockRunner = require('./helpers.js').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Doc reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
-  beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
-  });
+  var options = {};
+  var runReporter = makeRunReporter(Doc);
 
   afterEach(function() {
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe('on suite', function() {
@@ -32,8 +25,7 @@ describe('Doc reporter', function() {
       };
       it('should log html with indents and expected title', function() {
         runner = createMockRunner('suite', 'suite', null, null, suite);
-        Doc.call(this, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter(this, runner, options);
         var expectedArray = [
           '    <section class="suite">\n',
           '      <h1>' + expectedTitle + '</h1>\n',
@@ -48,8 +40,7 @@ describe('Doc reporter', function() {
         };
         expectedTitle = '&#x3C;div&#x3E;' + expectedTitle + '&#x3C;/div&#x3E;';
         runner = createMockRunner('suite', 'suite', null, null, suite);
-        Doc.call(this, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter(this, runner, options);
         var expectedArray = [
           '    <section class="suite">\n',
           '      <h1>' + expectedTitle + '</h1>\n',
@@ -64,8 +55,7 @@ describe('Doc reporter', function() {
       };
       it('should not log any html', function() {
         runner = createMockRunner('suite', 'suite', null, null, suite);
-        Doc.call(this, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter(this, runner, options);
         expect(stdout, 'to be empty');
       });
     });
@@ -78,8 +68,7 @@ describe('Doc reporter', function() {
       };
       it('should log expected html with indents', function() {
         runner = createMockRunner('suite end', 'suite end', null, null, suite);
-        Doc.call(this, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter(this, runner, options);
         var expectedArray = ['  </dl>\n', '</section>\n'];
         expect(stdout, 'to equal', expectedArray);
       });
@@ -90,8 +79,7 @@ describe('Doc reporter', function() {
       };
       it('should not log any html', function() {
         runner = createMockRunner('suite end', 'suite end', null, null, suite);
-        Doc.call(this, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter(this, runner, options);
         expect(stdout, 'to be empty');
       });
     });
@@ -109,8 +97,7 @@ describe('Doc reporter', function() {
     };
     it('should log html with indents and expected title and body', function() {
       runner = createMockRunner('pass', 'pass', null, null, test);
-      Doc.call(this, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter(this, runner, options);
       var expectedArray = [
         '    <dt>' + expectedTitle + '</dt>\n',
         '    <dd><pre><code>' + expectedBody + '</code></pre></dd>\n'
@@ -128,8 +115,7 @@ describe('Doc reporter', function() {
       var expectedEscapedBody =
         '&#x3C;div&#x3E;' + expectedBody + '&#x3C;/div&#x3E;';
       runner = createMockRunner('pass', 'pass', null, null, test);
-      Doc.call(this, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter(this, runner, options);
       var expectedArray = [
         '    <dt>' + expectedEscapedTitle + '</dt>\n',
         '    <dd><pre><code>' + expectedEscapedBody + '</code></pre></dd>\n'
@@ -158,8 +144,7 @@ describe('Doc reporter', function() {
         test,
         expectedError
       );
-      Doc.call(this, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter(this, runner, options);
       var expectedArray = [
         '    <dt class="error">' + expectedTitle + '</dt>\n',
         '    <dd class="error"><pre><code>' +
@@ -190,8 +175,7 @@ describe('Doc reporter', function() {
         test,
         unescapedError
       );
-      Doc.call(this, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter(this, runner, options);
       var expectedArray = [
         '    <dt class="error">' + expectedEscapedTitle + '</dt>\n',
         '    <dd class="error"><pre><code>' +
diff --git a/test/reporters/dot.spec.js b/test/reporters/dot.spec.js
index 0940d8be5f..472ec63d01 100644
--- a/test/reporters/dot.spec.js
+++ b/test/reporters/dot.spec.js
@@ -5,42 +5,17 @@ var Dot = reporters.Dot;
 var Base = reporters.Base;
 
 var createMockRunner = require('./helpers.js').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Dot reporter', function() {
-  var stdout;
   var runner;
   var useColors;
   var windowWidth;
   var color;
-  var showOutput = false;
-
-  /**
-   * Run reporter using stream reassignment to capture output.
-   *
-   * @param {Object} stubSelf - Reporter-like stub instance
-   * @param {Runner} runner - Mock instance
-   * @param {boolean} [tee=false] - If `true`, echo captured output to screen
-   */
-  function runReporter(stubSelf, runner, tee) {
-    // Reassign stream in order to make a copy of all reporter output
-    var stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      if (tee) {
-        stdoutWrite.call(process.stdout, string, enc, callback);
-      }
-    };
-
-    // Invoke reporter
-    Dot.call(stubSelf, runner);
-
-    // Revert stream reassignment here so reporter output
-    // can't be corrupted if any test assertions throw
-    process.stdout.write = stdoutWrite;
-  }
+  var options = {};
+  var runReporter = makeRunReporter(Dot);
 
   beforeEach(function() {
-    stdout = [];
     useColors = Base.useColors;
     windowWidth = Base.window.width;
     color = Base.color;
@@ -61,7 +36,7 @@ describe('Dot reporter', function() {
   describe('on start', function() {
     it('should write a newline', function() {
       runner = createMockRunner('start', 'start');
-      runReporter({epilogue: function() {}}, runner, showOutput);
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
       var expectedArray = ['\n'];
       expect(stdout, 'to equal', expectedArray);
     });
@@ -73,7 +48,7 @@ describe('Dot reporter', function() {
       });
       it('should write a newline followed by a comma', function() {
         runner = createMockRunner('pending', 'pending');
-        runReporter({epilogue: function() {}}, runner, showOutput);
+        var stdout = runReporter({epilogue: function() {}}, runner, options);
         var expectedArray = ['\n  ', 'pending_' + Base.symbols.comma];
         expect(stdout, 'to equal', expectedArray);
       });
@@ -81,7 +56,7 @@ describe('Dot reporter', function() {
     describe('if window width is equal to or less than 1', function() {
       it('should write a comma', function() {
         runner = createMockRunner('pending', 'pending');
-        runReporter({epilogue: function() {}}, runner, showOutput);
+        var stdout = runReporter({epilogue: function() {}}, runner, options);
         var expectedArray = ['pending_' + Base.symbols.comma];
         expect(stdout, 'to equal', expectedArray);
       });
@@ -101,7 +76,7 @@ describe('Dot reporter', function() {
       describe('if test speed is fast', function() {
         it('should write a newline followed by a dot', function() {
           runner = createMockRunner('pass', 'pass', null, null, test);
-          runReporter({epilogue: function() {}}, runner, showOutput);
+          var stdout = runReporter({epilogue: function() {}}, runner, options);
           expect(test.speed, 'to equal', 'fast');
           var expectedArray = ['\n  ', 'fast_' + Base.symbols.dot];
           expect(stdout, 'to equal', expectedArray);
@@ -112,7 +87,7 @@ describe('Dot reporter', function() {
       describe('if test speed is fast', function() {
         it('should write a grey dot', function() {
           runner = createMockRunner('pass', 'pass', null, null, test);
-          runReporter({epilogue: function() {}}, runner, showOutput);
+          var stdout = runReporter({epilogue: function() {}}, runner, options);
           expect(test.speed, 'to equal', 'fast');
           var expectedArray = ['fast_' + Base.symbols.dot];
           expect(stdout, 'to equal', expectedArray);
@@ -122,7 +97,7 @@ describe('Dot reporter', function() {
         it('should write a yellow dot', function() {
           test.duration = 2;
           runner = createMockRunner('pass', 'pass', null, null, test);
-          runReporter({epilogue: function() {}}, runner, showOutput);
+          var stdout = runReporter({epilogue: function() {}}, runner, options);
           expect(test.speed, 'to equal', 'medium');
           var expectedArray = ['medium_' + Base.symbols.dot];
           expect(stdout, 'to equal', expectedArray);
@@ -132,7 +107,7 @@ describe('Dot reporter', function() {
         it('should write a bright yellow dot', function() {
           test.duration = 3;
           runner = createMockRunner('pass', 'pass', null, null, test);
-          runReporter({epilogue: function() {}}, runner, showOutput);
+          var stdout = runReporter({epilogue: function() {}}, runner, options);
           expect(test.speed, 'to equal', 'slow');
           var expectedArray = ['bright-yellow_' + Base.symbols.dot];
           expect(stdout, 'to equal', expectedArray);
@@ -152,7 +127,7 @@ describe('Dot reporter', function() {
       });
       it('should write a newline followed by an exclamation mark', function() {
         runner = createMockRunner('fail', 'fail', null, null, test);
-        runReporter({epilogue: function() {}}, runner, showOutput);
+        var stdout = runReporter({epilogue: function() {}}, runner, options);
         var expectedArray = ['\n  ', 'fail_' + Base.symbols.bang];
         expect(stdout, 'to equal', expectedArray);
       });
@@ -160,7 +135,7 @@ describe('Dot reporter', function() {
     describe('if window width is equal to or less than 1', function() {
       it('should write an exclamation mark', function() {
         runner = createMockRunner('fail', 'fail', null, null, test);
-        runReporter({epilogue: function() {}}, runner, showOutput);
+        var stdout = runReporter({epilogue: function() {}}, runner, options);
         var expectedArray = ['fail_' + Base.symbols.bang];
         expect(stdout, 'to equal', expectedArray);
       });
@@ -173,7 +148,7 @@ describe('Dot reporter', function() {
       var epilogue = function() {
         epilogueCalled = true;
       };
-      runReporter({epilogue: epilogue}, runner, showOutput);
+      runReporter({epilogue: epilogue}, runner, options);
       expect(epilogueCalled, 'to be', true);
     });
   });
diff --git a/test/reporters/helpers.js b/test/reporters/helpers.js
index e0c6604216..4da36fa600 100644
--- a/test/reporters/helpers.js
+++ b/test/reporters/helpers.js
@@ -155,9 +155,51 @@ function makeExpectedTest(
   };
 }
 
+/**
+ * Creates closure with reference to the reporter class constructor.
+ *
+ * @param {Function} ctor - Reporter class constructor
+ * @return {createRunReporterFunction~runReporter}
+ */
+function createRunReporterFunction(ctor) {
+  /**
+   * Run reporter using stream reassignment to capture output.
+   *
+   * @param {Object} stubSelf - Reporter-like stub instance
+   * @param {Runner} runner - Mock instance
+   * @param {Object} [options] - Reporter configuration settings
+   * @param {boolean} [tee=false] - Whether to echo output to screen
+   * @return {string[]} Lines of output written to `stdout`
+   */
+  var runReporter = function(stubSelf, runner, options, tee) {
+    var stdout = [];
+
+    // Reassign stream in order to make a copy of all reporter output
+    var stdoutWrite = process.stdout.write;
+    process.stdout.write = function(string, enc, callback) {
+      stdout.push(string);
+      if (tee) {
+        stdoutWrite.call(process.stdout, string, enc, callback);
+      }
+    };
+
+    // Invoke reporter
+    ctor.call(stubSelf, runner, options);
+
+    // Revert stream reassignment here so reporter output
+    // can't be corrupted if any test assertions throw
+    process.stdout.write = stdoutWrite;
+
+    return stdout;
+  };
+
+  return runReporter;
+}
+
 module.exports = {
-  createMockRunner: createMockRunner,
-  makeTest: makeTest,
   createElements: createElements,
-  makeExpectedTest: makeExpectedTest
+  createMockRunner: createMockRunner,
+  createRunReporterFunction: createRunReporterFunction,
+  makeExpectedTest: makeExpectedTest,
+  makeTest: makeTest
 };
diff --git a/test/reporters/json-stream.spec.js b/test/reporters/json-stream.spec.js
index 3c5e1831f2..8c9fcfff35 100644
--- a/test/reporters/json-stream.spec.js
+++ b/test/reporters/json-stream.spec.js
@@ -5,12 +5,12 @@ var JSONStream = reporters.JSONStream;
 
 var createMockRunner = require('./helpers').createMockRunner;
 var makeExpectedTest = require('./helpers').makeExpectedTest;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
-describe('Json Stream reporter', function() {
+describe('JSON Stream reporter', function() {
   var runner;
-  var stdout;
-  var stdoutWrite;
-
+  var options = {};
+  var runReporter = makeRunReporter(JSONStream);
   var expectedTitle = 'some title';
   var expectedFullTitle = 'full title';
   var expectedDuration = 1000;
@@ -27,17 +27,8 @@ describe('Json Stream reporter', function() {
     message: expectedErrorMessage
   };
 
-  beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
-  });
-
   afterEach(function() {
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe('on start', function() {
@@ -45,9 +36,7 @@ describe('Json Stream reporter', function() {
       runner = createMockRunner('start', 'start');
       var expectedTotal = 12;
       runner.total = expectedTotal;
-      JSONStream.call({}, runner);
-
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({}, runner, options);
 
       expect(
         stdout[0],
@@ -60,9 +49,7 @@ describe('Json Stream reporter', function() {
   describe('on pass', function() {
     it('should write stringified test data', function() {
       runner = createMockRunner('pass', 'pass', null, null, expectedTest);
-      JSONStream.call({}, runner);
-
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({}, runner, options);
 
       expect(
         stdout[0],
@@ -93,9 +80,7 @@ describe('Json Stream reporter', function() {
           expectedError
         );
 
-        JSONStream.call({}, runner);
-
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
         expect(
           stdout[0],
@@ -129,8 +114,7 @@ describe('Json Stream reporter', function() {
           expectedError
         );
 
-        JSONStream.call({}, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter(this, runner, options);
 
         expect(
           stdout[0],
@@ -154,8 +138,7 @@ describe('Json Stream reporter', function() {
   describe('on end', function() {
     it('should write end details', function() {
       runner = createMockRunner('end', 'end');
-      JSONStream.call({}, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter(this, runner, options);
       expect(stdout[0], 'to match', /end/);
     });
   });
diff --git a/test/reporters/landing.spec.js b/test/reporters/landing.spec.js
index da4134ce70..1fee291e41 100644
--- a/test/reporters/landing.spec.js
+++ b/test/reporters/landing.spec.js
@@ -5,11 +5,12 @@ var Landing = reporters.Landing;
 var Base = reporters.Base;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Landing reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
+  var options = {};
+  var runReporter = makeRunReporter(Landing);
   var useColors;
   var windowWidth;
   var resetCode = '\u001b[0m';
@@ -25,12 +26,6 @@ describe('Landing reporter', function() {
   ];
 
   beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
     useColors = Base.useColors;
     Base.useColors = false;
     windowWidth = Base.window.width;
@@ -40,7 +35,7 @@ describe('Landing reporter', function() {
   afterEach(function() {
     Base.useColors = useColors;
     Base.window.width = windowWidth;
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe('on start', function() {
@@ -48,9 +43,7 @@ describe('Landing reporter', function() {
       var cachedCursor = Base.cursor;
       Base.cursor.hide = function() {};
       runner = createMockRunner('start', 'start');
-      Landing.call({}, runner);
-
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({}, runner, options);
 
       expect(stdout[0], 'to equal', '\n\n\n  ');
       Base.cursor = cachedCursor;
@@ -63,9 +56,7 @@ describe('Landing reporter', function() {
         calledCursorHide = true;
       };
       runner = createMockRunner('start', 'start');
-      Landing.call({}, runner);
-
-      process.stdout.write = stdoutWrite;
+      runReporter({}, runner, options);
       expect(calledCursorHide, 'to be', true);
 
       Base.cursor = cachedCursor;
@@ -80,9 +71,7 @@ describe('Landing reporter', function() {
         };
         runner = createMockRunner('test end', 'test end', null, null, test);
         runner.total = 12;
-        Landing.call({}, runner);
-
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
         expect(stdout, 'to equal', expectedArray);
       });
@@ -94,9 +83,7 @@ describe('Landing reporter', function() {
         };
         runner = createMockRunner('test end', 'test end', null, null, test);
 
-        Landing.call({}, runner);
-
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
         expect(stdout, 'to equal', expectedArray);
       });
@@ -112,16 +99,16 @@ describe('Landing reporter', function() {
       runner = createMockRunner('end', 'end');
 
       var calledEpilogue = false;
-      Landing.call(
+      runReporter(
         {
           epilogue: function() {
             calledEpilogue = true;
           }
         },
-        runner
+        runner,
+        options
       );
 
-      process.stdout.write = stdoutWrite;
       expect(calledEpilogue, 'to be', true);
       expect(calledCursorShow, 'to be', true);
 
diff --git a/test/reporters/list.spec.js b/test/reporters/list.spec.js
index 7b9c74fb43..78895796c4 100644
--- a/test/reporters/list.spec.js
+++ b/test/reporters/list.spec.js
@@ -5,11 +5,12 @@ var List = reporters.List;
 var Base = reporters.Base;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('List reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
+  var options = {};
+  var runReporter = makeRunReporter(List);
   var useColors;
   var expectedTitle = 'some title';
   var expectedDuration = 100;
@@ -21,27 +22,20 @@ describe('List reporter', function() {
     slow: function() {}
   };
   beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
     useColors = Base.useColors;
     Base.useColors = false;
   });
 
   afterEach(function() {
     Base.useColors = useColors;
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe('on start and test', function() {
     it('should write expected new line and title to the console', function() {
       runner = createMockRunner('start test', 'start', 'test', null, test);
-      List.call({epilogue: function() {}}, runner);
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
 
-      process.stdout.write = stdoutWrite;
       var startString = '\n';
       var testString = '    ' + expectedTitle + ': ';
       var expectedArray = [startString, testString];
@@ -51,9 +45,7 @@ describe('List reporter', function() {
   describe('on pending', function() {
     it('should write expected title to the console', function() {
       runner = createMockRunner('pending test', 'pending', null, null, test);
-      List.call({epilogue: function() {}}, runner);
-
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
 
       expect(stdout[0], 'to equal', '  - ' + expectedTitle + '\n');
     });
@@ -66,9 +58,7 @@ describe('List reporter', function() {
         calledCursorCR = true;
       };
       runner = createMockRunner('pass', 'pass', null, null, test);
-      List.call({epilogue: function() {}}, runner);
-
-      process.stdout.write = stdoutWrite;
+      runReporter({epilogue: function() {}}, runner, options);
 
       expect(calledCursorCR, 'to be', true);
 
@@ -81,9 +71,7 @@ describe('List reporter', function() {
       var cachedCursor = Base.cursor;
       Base.cursor.CR = function() {};
       runner = createMockRunner('pass', 'pass', null, null, test);
-      List.call({epilogue: function() {}}, runner);
-
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
 
       expect(
         stdout[0],
@@ -109,9 +97,7 @@ describe('List reporter', function() {
         calledCursorCR = true;
       };
       runner = createMockRunner('fail', 'fail', null, null, test);
-      List.call({epilogue: function() {}}, runner);
-
-      process.stdout.write = stdoutWrite;
+      runReporter({epilogue: function() {}}, runner, options);
 
       expect(calledCursorCR, 'to be', true);
 
@@ -122,9 +108,7 @@ describe('List reporter', function() {
       var expectedErrorCount = 1;
       Base.cursor.CR = function() {};
       runner = createMockRunner('fail', 'fail', null, null, test);
-      List.call({epilogue: function() {}}, runner);
-
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
 
       expect(
         stdout[0],
@@ -140,6 +124,7 @@ describe('List reporter', function() {
       var checked = false;
       var err;
       test = {};
+      runner = createMockRunner('fail', 'fail', null, null, test);
       runner.on = runner.once = function(event, callback) {
         if (!checked && event === 'fail') {
           err = new Error('fake failure object with actual/expected');
@@ -150,9 +135,8 @@ describe('List reporter', function() {
           checked = true;
         }
       };
-      List.call({epilogue: function() {}}, runner);
+      runReporter({epilogue: function() {}}, runner, options);
 
-      process.stdout.write = stdoutWrite;
       expect(typeof err.actual, 'to be', 'string');
       expect(typeof err.expected, 'to be', 'string');
     });
@@ -162,15 +146,15 @@ describe('List reporter', function() {
     it('should call epilogue', function() {
       var calledEpilogue = false;
       runner = createMockRunner('end', 'end');
-      List.call(
+      runReporter(
         {
           epilogue: function() {
             calledEpilogue = true;
           }
         },
-        runner
+        runner,
+        options
       );
-      process.stdout.write = stdoutWrite;
 
       expect(calledEpilogue, 'to be', true);
     });
diff --git a/test/reporters/markdown.spec.js b/test/reporters/markdown.spec.js
index f6fc63f119..842d7c7643 100644
--- a/test/reporters/markdown.spec.js
+++ b/test/reporters/markdown.spec.js
@@ -4,26 +4,18 @@ var reporters = require('../../').reporters;
 var Markdown = reporters.Markdown;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Markdown reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
+  var options = {};
+  var runReporter = makeRunReporter(Markdown);
   var expectedTitle = 'expected title';
   var expectedFullTitle = 'full title';
   var sluggedFullTitle = 'full-title';
 
-  beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
-  });
-
   afterEach(function() {
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe("on 'suite'", function() {
@@ -51,8 +43,7 @@ describe('Markdown reporter', function() {
         expectedSuite
       );
       runner.suite = expectedSuite;
-      Markdown.call({}, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({}, runner, options);
 
       var expectedArray = [
         '# TOC\n',
@@ -97,8 +88,7 @@ describe('Markdown reporter', function() {
       };
       runner = createMockRunner('pass end', 'pass', 'end', null, expectedTest);
       runner.suite = expectedSuite;
-      Markdown.call({}, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({}, runner, options);
 
       var expectedArray = [
         '# TOC\n',
diff --git a/test/reporters/min.spec.js b/test/reporters/min.spec.js
index 30b05126ec..f88adf31d7 100644
--- a/test/reporters/min.spec.js
+++ b/test/reporters/min.spec.js
@@ -4,31 +4,22 @@ var reporters = require('../../').reporters;
 var Min = reporters.Min;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Min reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
-
-  beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
-  });
+  var options = {};
+  var runReporter = makeRunReporter(Min);
 
   afterEach(function() {
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe('on start', function() {
     it('should clear screen then set cursor position', function() {
       runner = createMockRunner('start', 'start');
-      Min.call({epilogue: function() {}}, runner);
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
 
-      process.stdout.write = stdoutWrite;
       var expectedArray = ['\u001b[2J', '\u001b[1;3H'];
       expect(stdout, 'to equal', expectedArray);
     });
@@ -38,15 +29,15 @@ describe('Min reporter', function() {
     it('should call epilogue', function() {
       var calledEpilogue = false;
       runner = createMockRunner('end', 'end');
-      Min.call(
+      runReporter(
         {
           epilogue: function() {
             calledEpilogue = true;
           }
         },
-        runner
+        runner,
+        options
       );
-      process.stdout.write = stdoutWrite;
 
       expect(calledEpilogue, 'to be', true);
     });
diff --git a/test/reporters/nyan.spec.js b/test/reporters/nyan.spec.js
index 1296ab1195..96bbda6766 100644
--- a/test/reporters/nyan.spec.js
+++ b/test/reporters/nyan.spec.js
@@ -5,41 +5,33 @@ var NyanCat = reporters.Nyan;
 var Base = reporters.Base;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Nyan reporter', function() {
   describe('events', function() {
     var runner;
-    var stdout;
-    var stdoutWrite;
     var calledDraw;
-
-    beforeEach(function() {
-      stdout = [];
-      stdoutWrite = process.stdout.write;
-      process.stdout.write = function(string, enc, callback) {
-        stdout.push(string);
-        stdoutWrite.call(process.stdout, string, enc, callback);
-      };
-    });
+    var options = {};
+    var runReporter = makeRunReporter(NyanCat);
 
     afterEach(function() {
-      process.stdout.write = stdoutWrite;
+      runner = undefined;
     });
 
     describe('on start', function() {
       it('should call draw', function() {
         calledDraw = false;
         runner = createMockRunner('start', 'start');
-        NyanCat.call(
+        runReporter(
           {
             draw: function() {
               calledDraw = true;
             },
             generateColors: function() {}
           },
-          runner
+          runner,
+          options
         );
-        process.stdout.write = stdoutWrite;
 
         expect(calledDraw, 'to be', true);
       });
@@ -48,16 +40,16 @@ describe('Nyan reporter', function() {
       it('should call draw', function() {
         calledDraw = false;
         runner = createMockRunner('pending', 'pending');
-        NyanCat.call(
+        runReporter(
           {
             draw: function() {
               calledDraw = true;
             },
             generateColors: function() {}
           },
-          runner
+          runner,
+          options
         );
-        process.stdout.write = stdoutWrite;
 
         expect(calledDraw, 'to be', true);
       });
@@ -70,16 +62,16 @@ describe('Nyan reporter', function() {
           slow: function() {}
         };
         runner = createMockRunner('pass', 'pass', null, null, test);
-        NyanCat.call(
+        runReporter(
           {
             draw: function() {
               calledDraw = true;
             },
             generateColors: function() {}
           },
-          runner
+          runner,
+          options
         );
-        process.stdout.write = stdoutWrite;
 
         expect(calledDraw, 'to be', true);
       });
@@ -91,16 +83,16 @@ describe('Nyan reporter', function() {
           err: ''
         };
         runner = createMockRunner('fail', 'fail', null, null, test);
-        NyanCat.call(
+        runReporter(
           {
             draw: function() {
               calledDraw = true;
             },
             generateColors: function() {}
           },
-          runner
+          runner,
+          options
         );
-        process.stdout.write = stdoutWrite;
 
         expect(calledDraw, 'to be', true);
       });
@@ -109,7 +101,7 @@ describe('Nyan reporter', function() {
       it('should call epilogue', function() {
         var calledEpilogue = false;
         runner = createMockRunner('end', 'end');
-        NyanCat.call(
+        runReporter(
           {
             draw: function() {},
             generateColors: function() {},
@@ -117,28 +109,28 @@ describe('Nyan reporter', function() {
               calledEpilogue = true;
             }
           },
-          runner
+          runner,
+          options
         );
-        process.stdout.write = stdoutWrite;
 
         expect(calledEpilogue, 'to be', true);
       });
       it('should write numberOfLines amount of new lines', function() {
         var expectedNumberOfLines = 4;
         runner = createMockRunner('end', 'end');
-        NyanCat.call(
+        var stdout = runReporter(
           {
             draw: function() {},
             generateColors: function() {},
             epilogue: function() {}
           },
-          runner
+          runner,
+          options
         );
 
         var arrayOfNewlines = stdout.filter(function(value) {
           return value === '\n';
         });
-        process.stdout.write = stdoutWrite;
 
         expect(arrayOfNewlines, 'to have length', expectedNumberOfLines);
       });
@@ -149,16 +141,16 @@ describe('Nyan reporter', function() {
           showCalled = true;
         };
         runner = createMockRunner('end', 'end');
-        NyanCat.call(
+        runReporter(
           {
             draw: function() {},
             generateColors: function() {},
             epilogue: function() {}
           },
-          runner
+          runner,
+          options
         );
 
-        process.stdout.write = stdoutWrite;
         expect(showCalled, 'to be', true);
         Base.cursor.show = cachedShow;
       });
@@ -199,7 +191,6 @@ describe('Nyan reporter', function() {
           cursorUp: function() {}
         });
 
-        process.stdout.write = stdoutWrite;
         var expectedArray = [
           '\u001b[0C',
           '_,------,',
@@ -235,7 +226,6 @@ describe('Nyan reporter', function() {
           cursorUp: function() {}
         });
 
-        // process.stdout.write = stdoutWrite;
         var expectedArray = [
           '\u001b[0C',
           '_,------,',
@@ -276,7 +266,6 @@ describe('Nyan reporter', function() {
       var expectedNumber = 25;
 
       nyanCat.cursorDown(expectedNumber);
-      process.stdout.write = stdoutWrite;
       var expectedArray = ['\u001b[' + expectedNumber + 'B'];
       expect(stdout, 'to equal', expectedArray);
     });
@@ -303,7 +292,6 @@ describe('Nyan reporter', function() {
       var expectedNumber = 25;
 
       nyanCat.cursorUp(expectedNumber);
-      process.stdout.write = stdoutWrite;
       var expectedArray = ['\u001b[' + expectedNumber + 'A'];
       expect(stdout, 'to equal', expectedArray);
     });
@@ -432,13 +420,16 @@ describe('Nyan reporter', function() {
     var stdoutWrite;
     var stdout;
     var cachedColor;
+    var showOutput = false;
 
     beforeEach(function() {
       stdout = [];
       stdoutWrite = process.stdout.write;
       process.stdout.write = function(string, enc, callback) {
         stdout.push(string);
-        stdoutWrite.call(process.stdout, string, enc, callback);
+        if (showOutput) {
+          stdoutWrite.call(process.stdout, string, enc, callback);
+        }
       };
       cachedColor = Base.color;
       Base.color = function(type, n) {
@@ -496,13 +487,16 @@ describe('Nyan reporter', function() {
   describe('drawRainbow', function() {
     var stdoutWrite;
     var stdout;
+    var showOutput = false;
 
     beforeEach(function() {
       stdout = [];
       stdoutWrite = process.stdout.write;
       process.stdout.write = function(string, enc, callback) {
         stdout.push(string);
-        stdoutWrite.call(process.stdout, string, enc, callback);
+        if (showOutput) {
+          stdoutWrite.call(process.stdout, string, enc, callback);
+        }
       };
     });
 
@@ -524,7 +518,6 @@ describe('Nyan reporter', function() {
         numberOfLines: 1
       });
 
-      process.stdout.write = stdoutWrite;
       var expectedArray = [
         '\u001b[' + expectedWidth + 'C',
         expectedContents,
diff --git a/test/reporters/progress.spec.js b/test/reporters/progress.spec.js
index ef08ea5582..f19bb3988d 100644
--- a/test/reporters/progress.spec.js
+++ b/test/reporters/progress.spec.js
@@ -5,11 +5,13 @@ var Progress = reporters.Progress;
 var Base = reporters.Base;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Progress reporter', function() {
   var stdout;
   var stdoutWrite;
   var runner;
+  var runReporter = makeRunReporter(Progress);
 
   beforeEach(function() {
     stdout = [];
@@ -32,9 +34,8 @@ describe('Progress reporter', function() {
         calledCursorHide = true;
       };
       runner = createMockRunner('start', 'start');
-      Progress.call({}, runner);
+      runReporter({}, runner, {});
 
-      process.stdout.write = stdoutWrite;
       expect(calledCursorHide, 'to be', true);
 
       Base.cursor = cachedCursor;
@@ -55,9 +56,7 @@ describe('Progress reporter', function() {
         var expectedOptions = {};
         runner = createMockRunner('test end', 'test end');
         runner.total = expectedTotal;
-        Progress.call({}, runner, expectedOptions);
-
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, expectedOptions);
 
         expect(stdout, 'to equal', []);
 
@@ -93,9 +92,8 @@ describe('Progress reporter', function() {
         };
         runner = createMockRunner('test end', 'test end');
         runner.total = expectedTotal;
-        Progress.call({}, runner, options);
+        var stdout = runReporter({}, runner, options);
 
-        process.stdout.write = stdoutWrite;
         var expectedArray = [
           '\u001b[J',
           '  ' + expectedOpen,
@@ -122,16 +120,16 @@ describe('Progress reporter', function() {
       };
       runner = createMockRunner('end', 'end');
       var calledEpilogue = false;
-      Progress.call(
+      runReporter(
         {
           epilogue: function() {
             calledEpilogue = true;
           }
         },
-        runner
+        runner,
+        {}
       );
 
-      process.stdout.write = stdoutWrite;
       expect(calledEpilogue, 'to be', true);
       expect(calledCursorShow, 'to be', true);
 
diff --git a/test/reporters/spec.spec.js b/test/reporters/spec.spec.js
index 2f4eee33e5..5f7584e33e 100644
--- a/test/reporters/spec.spec.js
+++ b/test/reporters/spec.spec.js
@@ -5,28 +5,23 @@ var Spec = reporters.Spec;
 var Base = reporters.Base;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('Spec reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
+  var options = {};
+  var runReporter = makeRunReporter(Spec);
   var useColors;
   var expectedTitle = 'expectedTitle';
 
   beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
     useColors = Base.useColors;
     Base.useColors = false;
   });
 
   afterEach(function() {
     Base.useColors = useColors;
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
   });
 
   describe('on suite', function() {
@@ -35,8 +30,7 @@ describe('Spec reporter', function() {
         title: expectedTitle
       };
       runner = createMockRunner('suite', 'suite', null, null, suite);
-      Spec.call({epilogue: function() {}}, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
       var expectedArray = [expectedTitle + '\n'];
       expect(stdout, 'to equal', expectedArray);
     });
@@ -47,8 +41,7 @@ describe('Spec reporter', function() {
         title: expectedTitle
       };
       runner = createMockRunner('pending test', 'pending', null, null, suite);
-      Spec.call({epilogue: function() {}}, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
       var expectedArray = ['  - ' + expectedTitle + '\n'];
       expect(stdout, 'to equal', expectedArray);
     });
@@ -65,8 +58,7 @@ describe('Spec reporter', function() {
           }
         };
         runner = createMockRunner('pass', 'pass', null, null, test);
-        Spec.call({epilogue: function() {}}, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({epilogue: function() {}}, runner, options);
         var expectedString =
           '  ' +
           Base.symbols.ok +
@@ -90,8 +82,7 @@ describe('Spec reporter', function() {
           }
         };
         runner = createMockRunner('pass', 'pass', null, null, test);
-        Spec.call({epilogue: function() {}}, runner);
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({epilogue: function() {}}, runner, options);
         var expectedString =
           '  ' + Base.symbols.ok + ' ' + expectedTitle + '\n';
         expect(stdout[0], 'to be', expectedString);
@@ -105,8 +96,7 @@ describe('Spec reporter', function() {
         title: expectedTitle
       };
       runner = createMockRunner('fail', 'fail', null, null, test);
-      Spec.call({epilogue: function() {}}, runner);
-      process.stdout.write = stdoutWrite;
+      var stdout = runReporter({epilogue: function() {}}, runner, options);
       var expectedArray = ['  ' + functionCount + ') ' + expectedTitle + '\n'];
       expect(stdout, 'to equal', expectedArray);
     });
diff --git a/test/reporters/tap.spec.js b/test/reporters/tap.spec.js
index 5030cbde5c..c0a5419d37 100644
--- a/test/reporters/tap.spec.js
+++ b/test/reporters/tap.spec.js
@@ -4,22 +4,16 @@ var reporters = require('../../').reporters;
 var TAP = reporters.TAP;
 
 var createMockRunner = require('./helpers').createMockRunner;
+var makeRunReporter = require('./helpers.js').createRunReporterFunction;
 
 describe('TAP reporter', function() {
-  var stdout;
-  var stdoutWrite;
   var runner;
+  var runReporter = makeRunReporter(TAP);
   var expectedTitle = 'some title';
   var countAfterTestEnd = 2;
   var test;
 
   beforeEach(function() {
-    stdout = [];
-    stdoutWrite = process.stdout.write;
-    process.stdout.write = function(string, enc, callback) {
-      stdout.push(string);
-      stdoutWrite.call(process.stdout, string, enc, callback);
-    };
     test = {
       fullTitle: function() {
         return expectedTitle;
@@ -29,213 +23,456 @@ describe('TAP reporter', function() {
   });
 
   afterEach(function() {
-    process.stdout.write = stdoutWrite;
+    runner = undefined;
+    test = undefined;
   });
 
-  describe('on start', function() {
-    it('should hand runners suite into grepTotal and log the total', function() {
+  describe('TAP12 spec', function() {
+    var options = {};
+
+    describe('on start', function() {
       var expectedSuite = 'some suite';
       var expectedTotal = 10;
       var expectedString;
-      runner = createMockRunner('start', 'start');
-      runner.suite = expectedSuite;
-      runner.grepTotal = function(string) {
-        expectedString = string;
-        return expectedTotal;
-      };
-      TAP.call({}, runner);
-
-      var expectedArray = ['1..' + expectedTotal + '\n'];
-      process.stdout.write = stdoutWrite;
-
-      expect(stdout, 'to equal', expectedArray);
-      expect(expectedString, 'to be', expectedSuite);
+      var stdout;
+
+      before(function() {
+        runner = createMockRunner('start', 'start');
+        runner.suite = expectedSuite;
+        runner.grepTotal = function(string) {
+          expectedString = string;
+          return expectedTotal;
+        };
+        stdout = runReporter({}, runner, options);
+      });
+
+      it('should not write the TAP specification version', function() {
+        expect(stdout, 'not to contain', 'TAP version');
+      });
+      it('should write the number of tests that it plans to run', function() {
+        var expectedArray = ['1..' + expectedTotal + '\n'];
+        expect(stdout, 'to equal', expectedArray);
+        expect(expectedString, 'to be', expectedSuite);
+      });
     });
-  });
 
-  describe('on pending', function() {
-    it('should write expected message including count and title', function() {
-      runner = createMockRunner(
-        'start test',
-        'test end',
-        'pending',
-        null,
-        test
-      );
-      runner.suite = '';
-      runner.grepTotal = function() {};
-      TAP.call({}, runner);
-
-      process.stdout.write = stdoutWrite;
-
-      var expectedMessage =
-        'ok ' + countAfterTestEnd + ' ' + expectedTitle + ' # SKIP -\n';
-      expect(stdout[0], 'to equal', expectedMessage);
+    describe('on pending', function() {
+      it('should write expected message including count and title', function() {
+        runner = createMockRunner(
+          'start test',
+          'test end',
+          'pending',
+          null,
+          test
+        );
+        runner.suite = '';
+        runner.grepTotal = function() {};
+
+        var stdout = runReporter({}, runner, options);
+
+        var expectedMessage =
+          'ok ' + countAfterTestEnd + ' ' + expectedTitle + ' # SKIP -\n';
+        expect(stdout[0], 'to equal', expectedMessage);
+      });
     });
-  });
 
-  describe('on pass', function() {
-    it('should write expected message including count and title', function() {
-      runner = createMockRunner('start test', 'test end', 'pass', null, test);
+    describe('on pass', function() {
+      it('should write expected message including count and title', function() {
+        runner = createMockRunner('start test', 'test end', 'pass', null, test);
+        runner.suite = '';
+        runner.grepTotal = function() {};
 
-      runner.suite = '';
-      runner.grepTotal = function() {};
-      TAP.call({}, runner);
+        var stdout = runReporter({}, runner, options);
 
-      process.stdout.write = stdoutWrite;
+        var expectedMessage =
+          'ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n';
+        expect(stdout[0], 'to equal', expectedMessage);
+      });
+    });
+
+    describe('on fail', function() {
+      describe('if there is an error message', function() {
+        it('should write expected message and error message', function() {
+          var expectedErrorMessage = 'some error';
+          var error = {
+            message: expectedErrorMessage
+          };
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.on = function(event, callback) {
+            if (event === 'test end') {
+              callback();
+            } else if (event === 'fail') {
+              callback(test, error);
+            }
+          };
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
+            '  ' + expectedErrorMessage + '\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+
+      describe('if there is an error stack', function() {
+        it('should write expected message and stack', function() {
+          var expectedStack = 'some stack';
+          var error = {
+            stack: expectedStack
+          };
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
+            '  ' + expectedStack + '\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+
+      describe('if there is an error stack and error message', function() {
+        it('should write expected message and stack', function() {
+          var expectedStack = 'some stack';
+          var expectedErrorMessage = 'some error';
+          var error = {
+            stack: expectedStack,
+            message: expectedErrorMessage
+          };
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.on = function(event, callback) {
+            if (event === 'test end') {
+              callback();
+            } else if (event === 'fail') {
+              callback(test, error);
+            }
+          };
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
 
-      var expectedMessage =
-        'ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n';
-      expect(stdout[0], 'to equal', expectedMessage);
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
+            '  ' + expectedErrorMessage + '\n',
+            '  ' + expectedStack + '\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+
+      describe('if there is no error stack or error message', function() {
+        it('should write expected message only', function() {
+          var error = {};
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.on = runner.once = function(event, callback) {
+            if (event === 'test end') {
+              callback();
+            } else if (event === 'fail') {
+              callback(test, error);
+            }
+          };
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
     });
-  });
 
-  describe('on fail', function() {
-    describe('if there is an error message', function() {
-      it('should write expected message and error message', function() {
-        var expectedTitle = 'some title';
-        var countAfterTestEnd = 2;
-        var expectedErrorMessage = 'some error';
-        var test = {
-          fullTitle: function() {
-            return expectedTitle;
-          },
-          slow: function() {}
-        };
-        var error = {
-          message: expectedErrorMessage
-        };
-        runner.on = function(event, callback) {
-          if (event === 'test end') {
-            callback();
-          }
-          if (event === 'fail') {
-            callback(test, error);
-          }
-        };
+    describe('on end', function() {
+      it('should write total tests, passes and failures', function() {
+        var numberOfPasses = 1;
+        var numberOfFails = 1;
+        runner = createMockRunner('fail end pass', 'fail', 'end', 'pass', test);
         runner.suite = '';
         runner.grepTotal = function() {};
-        TAP.call({}, runner);
 
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
+        var totalTests = numberOfPasses + numberOfFails;
         var expectedArray = [
-          'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
-          '  ' + expectedErrorMessage + '\n'
+          'ok ' + numberOfPasses + ' ' + expectedTitle + '\n',
+          'not ok ' + numberOfFails + ' ' + expectedTitle + '\n',
+          '# tests ' + totalTests + '\n',
+          '# pass ' + numberOfPasses + '\n',
+          '# fail ' + numberOfFails + '\n'
         ];
         expect(stdout, 'to equal', expectedArray);
       });
     });
-    describe('if there is an error stack', function() {
-      it('should write expected message and stack', function() {
-        var expectedStack = 'some stack';
-        var error = {
-          stack: expectedStack
+  });
+
+  describe('TAP13 spec', function() {
+    var options = {
+      reporterOptions: {
+        tapVersion: '13'
+      }
+    };
+
+    describe('on start', function() {
+      var expectedSuite = 'some suite';
+      var expectedTotal = 10;
+      var expectedString;
+      var stdout;
+
+      before(function() {
+        runner = createMockRunner('start', 'start');
+        runner.suite = expectedSuite;
+        runner.grepTotal = function(string) {
+          expectedString = string;
+          return expectedTotal;
         };
+
+        stdout = runReporter({}, runner, options);
+      });
+
+      it('should write the TAP specification version', function() {
+        var tapVersion = options.reporterOptions.tapVersion;
+        var expectedFirstLine = 'TAP version ' + tapVersion + '\n';
+        expect(stdout[0], 'to equal', expectedFirstLine);
+      });
+      it('should write the number of tests that it plans to run', function() {
+        var expectedSecondLine = '1..' + expectedTotal + '\n';
+        expect(stdout[1], 'to equal', expectedSecondLine);
+        expect(expectedString, 'to be', expectedSuite);
+      });
+    });
+
+    describe('on pending', function() {
+      it('should write expected message including count and title', function() {
         runner = createMockRunner(
-          'test end fail',
+          'start test',
           'test end',
-          'fail',
+          'pending',
           null,
-          test,
-          error
+          test
         );
         runner.suite = '';
         runner.grepTotal = function() {};
-        TAP.call({}, runner);
 
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
-        var expectedArray = [
-          'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
-          '  ' + expectedStack + '\n'
-        ];
-        expect(stdout, 'to equal', expectedArray);
+        var expectedMessage =
+          'ok ' + countAfterTestEnd + ' ' + expectedTitle + ' # SKIP -\n';
+        expect(stdout[0], 'to equal', expectedMessage);
       });
     });
-    describe('if there is an error stack and error message', function() {
-      it('should write expected message and stack', function() {
-        var expectedTitle = 'some title';
-        var countAfterTestEnd = 2;
-        var expectedStack = 'some stack';
-        var expectedErrorMessage = 'some error';
-        var test = {
-          fullTitle: function() {
-            return expectedTitle;
-          },
-          slow: function() {}
-        };
-        var error = {
-          stack: expectedStack,
-          message: expectedErrorMessage
-        };
-        runner.on = function(event, callback) {
-          if (event === 'test end') {
-            callback();
-          }
-          if (event === 'fail') {
-            callback(test, error);
-          }
-        };
+
+    describe('on pass', function() {
+      it('should write expected message including count and title', function() {
+        runner = createMockRunner('start test', 'test end', 'pass', null, test);
         runner.suite = '';
         runner.grepTotal = function() {};
-        TAP.call({}, runner);
 
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
-        var expectedArray = [
-          'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
-          '  ' + expectedErrorMessage + '\n',
-          '  ' + expectedStack + '\n'
-        ];
-        expect(stdout, 'to equal', expectedArray);
+        var expectedMessage =
+          'ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n';
+        expect(stdout[0], 'to equal', expectedMessage);
       });
     });
-    describe('if there is no error stack or error message', function() {
-      it('should write expected message only', function() {
-        var error = {};
-        runner.on = runner.once = function(event, callback) {
-          if (event === 'test end') {
-            callback();
-          }
-          if (event === 'fail') {
-            callback(test, error);
-          }
-        };
+
+    describe('on fail', function() {
+      describe('if there is an error message', function() {
+        it('should write expected message and error message', function() {
+          var expectedErrorMessage = 'some error';
+          var error = {
+            message: expectedErrorMessage
+          };
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.on = function(event, callback) {
+            if (event === 'test end') {
+              callback();
+            } else if (event === 'fail') {
+              callback(test, error);
+            }
+          };
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
+            '  ---\n',
+            '    message: |-\n',
+            '      ' + expectedErrorMessage + '\n',
+            '  ...\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+
+      describe('if there is an error stack', function() {
+        it('should write expected message and stack', function() {
+          var expectedStack = 'some stack';
+          var error = {
+            stack: expectedStack
+          };
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
+            '  ---\n',
+            '    stack: |-\n',
+            '      ' + expectedStack + '\n',
+            '  ...\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+
+      describe('if there is an error stack and error message', function() {
+        it('should write expected message and stack', function() {
+          var expectedStack = 'some stack';
+          var expectedErrorMessage = 'some error';
+          var error = {
+            stack: expectedStack,
+            message: expectedErrorMessage
+          };
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.on = function(event, callback) {
+            if (event === 'test end') {
+              callback();
+            } else if (event === 'fail') {
+              callback(test, error);
+            }
+          };
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n',
+            '  ---\n',
+            '    message: |-\n',
+            '      ' + expectedErrorMessage + '\n',
+            '    stack: |-\n',
+            '      ' + expectedStack + '\n',
+            '  ...\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+
+      describe('if there is no error stack or error message', function() {
+        it('should write expected message only', function() {
+          var error = {};
+          runner = createMockRunner(
+            'test end fail',
+            'test end',
+            'fail',
+            null,
+            test,
+            error
+          );
+          runner.on = runner.once = function(event, callback) {
+            if (event === 'test end') {
+              callback();
+            } else if (event === 'fail') {
+              callback(test, error);
+            }
+          };
+          runner.suite = '';
+          runner.grepTotal = function() {};
+
+          var stdout = runReporter({}, runner, options);
+
+          var expectedArray = [
+            'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n'
+          ];
+          expect(stdout, 'to equal', expectedArray);
+        });
+      });
+    });
+
+    describe('on end', function() {
+      it('should write total tests, passes and failures', function() {
+        var numberOfPasses = 1;
+        var numberOfFails = 1;
+        runner = createMockRunner('fail end pass', 'fail', 'end', 'pass', test);
         runner.suite = '';
         runner.grepTotal = function() {};
-        TAP.call({}, runner);
 
-        process.stdout.write = stdoutWrite;
+        var stdout = runReporter({}, runner, options);
 
+        var totalTests = numberOfPasses + numberOfFails;
         var expectedArray = [
-          'not ok ' + countAfterTestEnd + ' ' + expectedTitle + '\n'
+          'ok ' + numberOfPasses + ' ' + expectedTitle + '\n',
+          'not ok ' + numberOfFails + ' ' + expectedTitle + '\n',
+          '# tests ' + totalTests + '\n',
+          '# pass ' + numberOfPasses + '\n',
+          '# fail ' + numberOfFails + '\n'
         ];
         expect(stdout, 'to equal', expectedArray);
       });
     });
   });
-
-  describe('on end', function() {
-    it('should write total tests, passes and failures', function() {
-      var numberOfPasses = 1;
-      var numberOfFails = 1;
-      runner = createMockRunner('fail end pass', 'fail', 'end', 'pass', test);
-      runner.suite = '';
-      runner.grepTotal = function() {};
-      TAP.call({}, runner);
-
-      process.stdout.write = stdoutWrite;
-
-      var totalTests = numberOfPasses + numberOfFails;
-      var expectedArray = [
-        'ok ' + numberOfPasses + ' ' + expectedTitle + '\n',
-        'not ok ' + numberOfFails + ' ' + expectedTitle + '\n',
-        '# tests ' + totalTests + '\n',
-        '# pass ' + numberOfPasses + '\n',
-        '# fail ' + numberOfFails + '\n'
-      ];
-      expect(stdout, 'to equal', expectedArray);
-    });
-  });
 });
diff --git a/test/reporters/xunit.spec.js b/test/reporters/xunit.spec.js
index 8108c50b78..42e9ca2c6e 100644
--- a/test/reporters/xunit.spec.js
+++ b/test/reporters/xunit.spec.js
@@ -18,6 +18,8 @@ describe('XUnit reporter', function() {
   var expectedClassName = 'fullTitle';
   var expectedTitle = 'some title';
   var expectedMessage = 'some message';
+  var expectedDiff =
+    '\n      + expected - actual\n\n      -foo\n      +bar\n      ';
   var expectedStack = 'some-stack';
   var expectedWrite = null;
 
@@ -214,6 +216,8 @@ describe('XUnit reporter', function() {
           },
           duration: 1000,
           err: {
+            actual: 'foo',
+            expected: 'bar',
             message: expectedMessage,
             stack: expectedStack
           }
@@ -235,6 +239,8 @@ describe('XUnit reporter', function() {
           '" time="1"><failure>' +
           expectedMessage +
           '\n' +
+          expectedDiff +
+          '\n' +
           expectedStack +
           '</failure></testcase>';
 
diff --git a/test/unit/mocha.spec.js b/test/unit/mocha.spec.js
index 4bd654915f..13e5a6db02 100644
--- a/test/unit/mocha.spec.js
+++ b/test/unit/mocha.spec.js
@@ -34,6 +34,16 @@ describe('Mocha', function() {
         });
       }
     );
+
+    it('should emit start event', function(done) {
+      var mocha = new Mocha(blankOpts);
+      mocha.run().on('start', done);
+    });
+
+    it('should emit end event', function(done) {
+      var mocha = new Mocha(blankOpts);
+      mocha.run().on('end', done);
+    });
   });
 
   describe('.addFile()', function() {
diff --git a/test/unit/runnable.spec.js b/test/unit/runnable.spec.js
index 9ea00b6d07..0fb29db6e5 100644
--- a/test/unit/runnable.spec.js
+++ b/test/unit/runnable.spec.js
@@ -46,18 +46,84 @@ describe('Runnable(title, fn)', function() {
   });
 
   describe('#timeout(ms)', function() {
-    it('should set the timeout', function() {
-      var run = new Runnable();
-      run.timeout(1000);
-      assert(run.timeout() === 1000);
+    var MIN_TIMEOUT = 0;
+    var MAX_TIMEOUT = 2147483647; // INT_MAX (32-bit signed integer)
+
+    describe('when value is less than lower bound', function() {
+      it('should clamp to lower bound given numeric', function() {
+        var run = new Runnable();
+        run.timeout(-1);
+        assert(run.timeout() === MIN_TIMEOUT);
+      });
+      // :TODO: Our internal version of `ms` can't handle negative time,
+      // but package version can. Skip this check until that change is merged.
+      it.skip('should clamp to lower bound given timestamp', function() {
+        var run = new Runnable();
+        run.timeout('-1 ms');
+        assert(run.timeout() === MIN_TIMEOUT);
+      });
     });
-  });
 
-  describe('#timeout(ms) when ms>2^31', function() {
-    it('should set disabled', function() {
-      var run = new Runnable();
-      run.timeout(1e10);
-      assert(run.enableTimeouts() === false);
+    describe('when value is equal to lower bound', function() {
+      it('should set the value and disable timeouts given numeric', function() {
+        var run = new Runnable();
+        run.timeout(MIN_TIMEOUT);
+        assert(run.timeout() === MIN_TIMEOUT);
+        assert(run.enableTimeouts() === false);
+      });
+      it('should set the value and disable timeouts given timestamp', function() {
+        var run = new Runnable();
+        run.timeout(MIN_TIMEOUT + 'ms');
+        assert(run.timeout() === MIN_TIMEOUT);
+        assert(run.enableTimeouts() === false);
+      });
+    });
+
+    describe('when value is within `setTimeout` bounds', function() {
+      var oneSecond = 1000;
+
+      it('should set the timeout given numeric', function() {
+        var run = new Runnable();
+        run.timeout(oneSecond);
+        assert(run.timeout() === oneSecond);
+        assert(run.enableTimeouts() === true);
+      });
+      it('should set the timeout given timestamp', function() {
+        var run = new Runnable();
+        run.timeout('1s');
+        assert(run.timeout() === oneSecond);
+        assert(run.enableTimeouts() === true);
+      });
+    });
+
+    describe('when value is equal to upper bound', function() {
+      it('should set the value and disable timeout given numeric', function() {
+        var run = new Runnable();
+        run.timeout(MAX_TIMEOUT);
+        assert(run.timeout() === MAX_TIMEOUT);
+        assert(run.enableTimeouts() === false);
+      });
+      it('should set the value and disable timeout given timestamp', function() {
+        var run = new Runnable();
+        run.timeout(MAX_TIMEOUT + 'ms');
+        assert(run.timeout() === MAX_TIMEOUT);
+        assert(run.enableTimeouts() === false);
+      });
+    });
+
+    describe('when value is greater than `setTimeout` limit', function() {
+      it('should clamp to upper bound given numeric', function() {
+        var run = new Runnable();
+        run.timeout(MAX_TIMEOUT + 1);
+        assert(run.timeout() === MAX_TIMEOUT);
+        assert(run.enableTimeouts() === false);
+      });
+      it('should clamp to upper bound given timestamp', function() {
+        var run = new Runnable();
+        run.timeout('24.9d'); // 2151360000ms
+        assert(run.timeout() === MAX_TIMEOUT);
+        assert(run.enableTimeouts() === false);
+      });
     });
   });