CLI: Fix --seed <file> arg confusion, Backport --seed=true support

* Fix `--seed <file>` arg confusion. This is now correctly interpreted
  as a file.

* Fix presence of "Running tests with seed:" message on CLI when preconfig
  qunit_config_seed is set via environment variable. Previously the
  seed was applied, but not printed because the printing logic only
  checked the CLI options, not QUnit.config.

* Add `--seed=true` to generate a new seed.
  This is backported from QUnit 3.0.0-alpha, and aligns the CLI with
  what was already supported via Preconfig, QUnit.config, and URL
  params.

Cherry-picked from 390a5b7 (3.0.0-dev).
> Ref #1691.

bin/qunit.js

@@ -31,8 +31,8 @@ program
     'reporters will be displayed')
   .option('--require <module>', 'specify a module or script to include before running ' +
     'any tests.', collect, [])
-  .option('--seed [value]', 'specify a seed to re-order your tests; ' +
-    'if specified without a value, a seed will be generated')
+  .option('--seed <value>', 'specify a seed to re-order your tests; ' +
+    'set to "true" to generate a new seed')
   .option('-w, --watch', 'watch files for changes and re-run the test suite')
   .parse(process.argv);
 

src/cli/run.js

@@ -55,12 +55,15 @@ async function run (args, options) {
 
   const seed = options.seed;
   if (seed) {
-    if (seed === true) {
-      QUnit.config.seed = Math.random().toString(36).slice(2);
+    if (seed === 'true' || seed === true) {
+      // NOTE: QUnit 3 will set preconfig qunit_config_seed from here.
+      // NOTE: This duplicates logic from /src/core/config.js. Consolidated in QUnit 3.
+      QUnit.config.seed = (Math.random().toString(36) + '0000000000').slice(2, 12);
     } else {
       QUnit.config.seed = seed;
     }
-
+  }
+  if (QUnit.config.seed) {
     console.log(`Running tests with seed: ${QUnit.config.seed}`);
   }
 

src/core/config.js

@@ -156,6 +156,12 @@ function readFlatPreconfigString (val, dest) {
   }
 }
 
+function readFlatPreconfigStringOrBoolean (val, dest) {
+  if (typeof val === 'boolean' || (typeof val === 'string' && val !== '')) {
+    config[dest] = val;
+  }
+}
+
 function readFlatPreconfigStringArray (val, dest) {
   if (typeof val === 'string' && val !== '') {
     config[dest] = [val];
@@ -178,7 +184,7 @@ function readFlatPreconfig (obj) {
   readFlatPreconfigBoolean(obj.qunit_config_reorder, 'reorder');
   readFlatPreconfigBoolean(obj.qunit_config_requireexpects, 'requireExpects');
   readFlatPreconfigBoolean(obj.qunit_config_scrolltop, 'scrolltop');
-  readFlatPreconfigString(obj.qunit_config_seed, 'seed');
+  readFlatPreconfigStringOrBoolean(obj.qunit_config_seed, 'seed');
   readFlatPreconfigStringArray(obj.qunit_config_testid, 'testId');
   readFlatPreconfigNumber(obj.qunit_config_testtimeout, 'testTimeout');
 }
@@ -200,4 +206,10 @@ if (preConfig) {
 // Push a loose unnamed module to the modules collection
 config.modules.push(config.currentModule);
 
+if (config.seed === 'true' || config.seed === true) {
+  // Generate a random seed
+  // Length of `Math.random()` fraction, in base 36, may vary from 6-14.
+  // Pad and take slice to a consistent 10-digit value.
+  config.seed = (Math.random().toString(36) + '0000000000').slice(2, 12);
+}
 export default config;

src/html-runner/urlparams.js

@@ -26,9 +26,11 @@ import { window } from '../globals';
   QUnit.config.testId = [].concat(urlParams.testId || []);
 
   // Test order randomization
-  if (urlParams.seed === true) {
-    // Generate a random seed if the option is specified without a value
-    QUnit.config.seed = Math.random().toString(36).slice(2);
+  // Generate a random seed if `?seed` is specified without a value (boolean true),
+  // or when set to the string "true".
+  if (urlParams.seed === 'true' || urlParams.seed === true) {
+    // NOTE: This duplicates logic from /src/core/config.js. Consolidated in QUnit 3.
+    QUnit.config.seed = (Math.random().toString(36) + '0000000000').slice(2, 12);
   } else if (urlParams.seed) {
     QUnit.config.seed = urlParams.seed;
   }

test/cli/cli-main.js

@@ -31,7 +31,8 @@ QUnit.module('CLI Main', () => {
         qunit_config_testtimeout: '7'
       }
     });
-    assert.equal(execution.snapshot, `TAP version 13
+    assert.equal(execution.snapshot, `Running tests with seed: dummyfirstyes
+TAP version 13
 ok 1 dummy
 not ok 2 slow
   ---
@@ -367,6 +368,38 @@ not ok 1 global failure
 # exit code: 1`);
   });
 
+  QUnit.test('--seed=true generates new random seed', async assert => {
+    const command = ['qunit', '--seed', 'true', 'basic-one.js', 'test/'];
+    const execution = await execute(command);
+
+    const actualHarness = execution.snapshot
+      .replace(/^(Running tests with seed: )([a-z0-9]{10,20})/g, (_m, m1) => {
+        return m1 + '0000000000';
+      })
+      .split('\n')
+      .filter(line => !line.startsWith('ok '))
+      .join('\n');
+
+    const actualResults = execution.snapshot
+      .replace(/^ok \d/gm, 'ok 0')
+      .split('\n')
+      .filter(line => line.startsWith('ok '))
+      .sort()
+      .join('\n');
+
+    assert.equal(actualHarness, `Running tests with seed: 0000000000
+TAP version 13
+1..3
+# pass 3
+# skip 0
+# todo 0
+# fail 0`);
+
+    assert.equal(actualResults, `ok 0 First > 1
+ok 0 Second > 1
+ok 0 Single > has a test`);
+  });
+
   QUnit.test('--require loads unknown module', async assert => {
     const command = ['qunit', 'basic-one.js', '--require', 'does-not-exist-at-all'];
     const execution = await execute(command);