feat(ui-karma-config,ui-scripts): --randomize test order flag

Change-Id: Iba9dbce33e002c8a2ab59391bd40cc0373d5e4b6
Reviewed-on: https://gerrit.instructure.com/184677
Tested-by: Jenkins
Reviewed-by: Jennifer Stern <jstern@instructure.com>
QA-Review: Jennifer Stern <jstern@instructure.com>
Product-Review: Jennifer Stern <jstern@instructure.com>

Author: omarkhan

packages/ui-karma-config/lib/index.js

@@ -23,9 +23,11 @@
  */
 const path = require('path')
 const constants = require('karma').constants
+const choma = require.resolve('choma')
 
 const noLaunchers = process.argv.some((arg) => arg === '--no-launch')
 const noHeadless = process.argv.some((arg) => arg === '--no-headless')
+const randomizeTestOrder = process.argv.some((arg) => arg === '--randomize')
 
 const baseWebpackConfig = require('@instructure/ui-webpack-config')
 
@@ -94,9 +96,10 @@ module.exports = function makeConfig ({
 
       frameworks: ['mocha', 'viewport'],
 
-      files: [bundle],
+      files: randomizeTestOrder ? [choma, bundle] : [bundle],
 
       preprocessors: {
+        [choma]: ['webpack'],
         [bundle]: ['webpack', 'sourcemap']
       },
 
@@ -156,7 +159,12 @@ module.exports = function makeConfig ({
         externals: {
           'react/lib/ExecutionEnvironment': true,
           'react/lib/ReactContext': true,
-          'react/addons': true
+          'react/addons': true,
+          // The karma webpack plugin exposes a mocha instance as
+          // `window.mocha`, but the mocha npm package exports the mocha
+          // contructor function. The choma script needs access to the mocha
+          // constructor so it can monkey-patch it for random test ordering.
+          'mocha': 'mocha.constructor'
         },
         resolveLoader: {
           alias: {

packages/ui-karma-config/package.json

@@ -18,6 +18,7 @@
   "dependencies": {
     "@instructure/config-loader": "^5",
     "@instructure/ui-webpack-config": "^5",
+    "choma": "^1",
     "globby": "^9.0.0",
     "karma": "^4.0.0",
     "karma-chrome-launcher": "^2.2.0",

packages/ui-scripts/lib/test/karma.js

@@ -44,6 +44,10 @@ if (argv.includes('--no-headless')) {
   args.push('--no-headless')
 }
 
+if (argv.includes('--randomize')) {
+  args.push('--randomize')
+}
+
 const browsersArgIndex = argv.findIndex(arg => arg.startsWith('--browsers='))
 
 if (browsersArgIndex) {

yarn.lock

@@ -4019,7 +4019,7 @@ chalk@2.4.1:
     escape-string-regexp "^1.0.5"
     supports-color "^5.3.0"
 
-chalk@2.4.2, chalk@^2.0.0, chalk@^2.0.1, chalk@^2.1.0, chalk@^2.3.0, chalk@^2.3.1, chalk@^2.4.1, chalk@^2.4.2:
+chalk@2.4.2, chalk@^2.0.0, chalk@^2.0.1, chalk@^2.1.0, chalk@^2.3.0, chalk@^2.3.1, chalk@^2.3.2, chalk@^2.4.1, chalk@^2.4.2:
   version "2.4.2"
   resolved "https://registry.npmjs.org/chalk/-/chalk-2.4.2.tgz#cd42541677a54333cf541a49108c1432b44c9424"
   integrity sha512-Mti+f9lpJNcwF4tWV8/OrTTtF1gZi+f8FqlyAdouralcFWFQWF2+NgCHShjkCb+IFBLq9buZwE1xckQU4peSuQ==
@@ -4130,6 +4130,14 @@ chokidar@^2.0.0, chokidar@^2.0.2, chokidar@^2.0.3:
   optionalDependencies:
     fsevents "^1.2.7"
 
+choma@^1:
+  version "1.2.1"
+  resolved "https://registry.npmjs.org/choma/-/choma-1.2.1.tgz#3467e5e1095ece975c48b74ded33ab771e2faaf4"
+  integrity sha512-4KwEouEHt6SfG8vYnN2gSJfq/cGmnY2gubnUgsgkRXzHoSRAgluX2YXQgDg6bTDWuOmUrTb/cfwMpNlvnnPZCg==
+  dependencies:
+    chalk "^2.3.2"
+    seedrandom "^2.4.3"
+
 chownr@^1.1.1:
   version "1.1.1"
   resolved "https://registry.npmjs.org/chownr/-/chownr-1.1.1.tgz#54726b8b8fff4df053c42187e801fb4412df1494"
@@ -14528,6 +14536,11 @@ script-ext-html-webpack-plugin@^2.1.3:
   dependencies:
     debug "^4.1.0"
 
+seedrandom@^2.4.3:
+  version "2.4.4"
+  resolved "https://registry.npmjs.org/seedrandom/-/seedrandom-2.4.4.tgz#b25ea98632c73e45f58b77cfaa931678df01f9ba"
+  integrity sha512-9A+PDmgm+2du77B5i0Ip2cxOqqHjgNxnBgglxLcX78A2D6c2rTo61z4jnVABpF4cKeDMDG+cmXXvdnqse2VqMA==
+
 seekout@^1.0.1:
   version "1.0.2"
   resolved "https://registry.npmjs.org/seekout/-/seekout-1.0.2.tgz#09ba9f1bd5b46fbb134718eb19a68382cbb1b9c9"