Add option to run a single Karma spec file

config/karma.config.js

@@ -12,8 +12,16 @@ if (webpackConfig.plugins) {
       plugin instanceof webpack.DefinePlugin
     );
   });
+} else {
+  webpackConfig.plugins = [];
 }
 
+webpackConfig.plugins.push(
+  new webpack.DefinePlugin({
+    TEST_FILE: JSON.stringify(process.env.TEST_FILE),
+  })
+);
+
 webpackConfig.devtool = 'cheap-inline-source-map';
 
 // Karma configuration

spec/javascripts/test_bundle.js

@@ -6,6 +6,7 @@ import '~/commons';
 
 import Vue from 'vue';
 import VueResource from 'vue-resource';
+import Translate from '~/vue_shared/translate';
 
 const isHeadlessChrome = /\bHeadlessChrome\//.test(navigator.userAgent);
 Vue.config.devtools = !isHeadlessChrome;
@@ -24,6 +25,7 @@ Vue.config.errorHandler = function (err) {
 };
 
 Vue.use(VueResource);
+Vue.use(Translate);
 
 // enable test fixtures
 jasmine.getFixtures().fixturesPath = '/base/spec/javascripts/fixtures';
@@ -61,11 +63,20 @@ beforeEach(() => {
   Vue.http.interceptors = builtinVueHttpInterceptors.slice();
 });
 
-// render all of our tests
+// eslint-disable-next-line no-undef
+let testFile = TEST_FILE;
+if (testFile) {
+  console.log(`Running only ${testFile}`);
+  testFile = testFile.replace(/^spec\/javascripts\//, '');
+  testFile = testFile.replace(/\.js$/, '');
+}
+
 const testsContext = require.context('.', true, /_spec$/);
 testsContext.keys().forEach(function (path) {
   try {
+    if (!testFile || path.indexOf(testFile) > -1) {
       testsContext(path);
+    }
   } catch (err) {
     console.error('[ERROR] Unable to load spec: ', path);
     describe('Test bundle', function () {