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HOWTO-tape-not-mocha.md

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Tape not Mocha

It may be hard to believe, but some people don't really like Mocha. Some of us prefer something simpler and less magical, like tape. We can still use coffee-coverage!

Setup

First install some necessary modules. Use --save-dev because these are only necessary for testing, not for the basic operation of your project.

npm install --save-dev istanbul coffee-coverage tape coffeetape faucet

faucet isn't required, since it is just a pretty-printer, and there are loads of alternatives -- pick the one you like. If you don't care for your tests to be pretty, then don't install any of them. Actually not even tape is really required, although that's what this HOWTO is about. The point is that coffee-coverage works with anything that runs your test code. In this example we use coffeetape (so e.g. test.coffee never gets transpiled to disk), but we could use plain node, plain coffee, tape, gulp, or whatever.

Write Tests

Let's say you have some code in index.coffee in the module directory. In that case your tests might look a bit like the following:

test = require 'tape'

test 'My Awesome Test, Section 1', (assert) ->
  assert.plan 1                       # if you don't call .plan(), call .end(),
  assert.doesNotThrow ->              # although .plan() is necessary for async
    require './index'
  , null, "requiring module shouldn't cause errors"

You can call test() any number of times, from any number of test files. Tools (like faucet) that understand TAP can handle it.

npm Scripts

If your tests are in a file in the module directory named test.coffee, then you could add the following to package.json:

"scripts": {
  "pretest": "coffeeCoverage --inst istanbul --exclude test.coffee,node_modules . .",
  "test": "istanbul cover --print none coffeetape test.coffee | faucet",
  "posttest": "istanbul report text-summary"
}

The pretest will transpile your coffeescript files into "instrumented" javascript files. Typically you'll want to exclude test files, so your coverage statistics are calculated with respect to your actual module, not to your module's tests. (node_modules is excluded by default, but if --exclude is specified it must be listed.) The --print none in the first call to instanbul is so that the summary report won't interfere with faucet. After that's done, printing the summary in posttest will look fine:

$ npm test

> test2@0.0.0 pretest <my_module>
> coffeeCoverage --inst istanbul --exclude test.coffee,node_modules . .

Instrumented 1 lines.

> test2@0.0.0 test <my_module>
> istanbul cover --print none coffeetape test.coffee | faucet

✓ My Awesome Test, Section 1
# tests 1
# pass  1
✓ ok

> test2@0.0.0 posttest <my_module>
> istanbul report text-summary


=============================== Coverage summary ===============================
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Functions    : 100% ( 2/2 )
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