CLI: Add --seed=true to generate a new seed

Fixes #1691.

bin/qunit.js

@@ -36,9 +36,9 @@ program
     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 enable randomized ordering of tests.\n'
+    + 'set to "true" to generate a new seed.'
   )
   .option('-w, --watch', 'watch files for changes and re-run the test suite')
   .parse(process.argv);

docs/api/config/seed.md

@@ -34,7 +34,7 @@ The provided string will be used as the seed in a pseudo-random number generator
 
 Randomly ordering your tests can help identify non-atomic tests which either depend on a previous test or are leaking state to subsequent tests.
 
-If `seed` is boolean true (or set as URL query parameter without a value), then QUnit will generate on-demand a new random value to use as seed. You can then read the seed at runtime from the configuration value, and use it to reproduce the same test sequence later.
+If `seed` is boolean true (or set as URL query parameter without a value), then QUnit will generate on-demand a new random value to use as seed. You can then read the seed from `QUnit.config.seed` at runtime, and use it to reproduce the same test sequence later.
 
 ## See also
 

src/cli/run.js

@@ -43,26 +43,20 @@ async function run (args, options) {
 
   const files = utils.getFilesFromArgs(args);
 
-  // Replace any previous instance, e.g. in watch mode
-  QUnit = globalThis.QUnit = requireQUnit();
-
   if (options.filter) {
-    QUnit.config.filter = options.filter;
+    globalThis.qunit_config_filter = options.filter;
   }
-
   if (options.module) {
-    QUnit.config.module = options.module;
+    globalThis.qunit_config_module = options.module;
+  }
+  if (options.seed) {
+    globalThis.qunit_config_seed = options.seed;
   }
 
-  const seed = options.seed;
-  if (seed) {
-    if (seed === true) {
-      // Length may vary from 6-14, pad to 10
-      QUnit.config.seed = Math.random().toString(36).slice(2).padEnd(10, '0');
-    } else {
-      QUnit.config.seed = seed;
-    }
+  // Replace any previous instance, e.g. in watch mode
+  QUnit = globalThis.QUnit = requireQUnit();
 
+  if (QUnit.config.seed) {
     console.log(`Running tests with seed: ${QUnit.config.seed}`);
   }
 

src/core/config.js

@@ -168,6 +168,12 @@ 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];
@@ -190,7 +196,7 @@ 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');
 
@@ -238,12 +244,13 @@ if (urlParams.testId) {
 readFlatPreconfigBoolean(urlParams.hidepassed, 'hidepassed');
 readFlatPreconfigBoolean(urlParams.noglobals, 'noglobals');
 readFlatPreconfigBoolean(urlParams.notrycatch, 'notrycatch');
-if (urlParams.seed === true) {
-  // Generate a random seed if the option is specified without a value
+readFlatPreconfigStringOrBoolean(urlParams.seed, 'seed');
+
+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.
   // TODO: Present this in HtmlReporter
-  config.seed = Math.random().toString(36).slice(2);
-} else {
-  readFlatPreconfigString(urlParams.seed, 'seed');
+  config.seed = (Math.random().toString(36) + '0000000000').slice(2, 12);
 }
-
 export default config;

test/cli/cli-main.js

@@ -33,7 +33,8 @@ QUnit.module('CLI Main', () => {
         qunit_config_notrycatch: 'false'
       }
     });
-    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
   ---
@@ -213,9 +214,8 @@ Bail out! Error: No tests matched the filter "no matches".
 # exit code: 1`);
   });
 
-  QUnit.test('--seed generates new random seed', async assert => {
-    // https://github.com/qunitjs/qunit/issues/1691
-    const command = ['qunit', '--seed', '--', 'basic-one.js', 'test/'];
+  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