Add Karma-style fixture helpers to Jest

spec/frontend/.eslintrc.yml

@@ -2,8 +2,13 @@
 env:
   jest/globals: true
 plugins:
-- jest
+  - jest
 settings:
   import/resolver:
     jest:
-      jestConfigFile: "jest.config.js"
+      jestConfigFile: 'jest.config.js'
+globals:
+  getJSONFixture: false
+  loadFixtures: false
+  preloadFixtures: false
+  setFixtures: false

spec/frontend/environment.js

@@ -6,6 +6,7 @@ const JSDOMEnvironment = require('jest-environment-jsdom');
 class CustomEnvironment extends JSDOMEnvironment {
   constructor(config, context) {
     super(config, context);
+
     Object.assign(context.console, {
       error(...args) {
         throw new ErrorWithStack(

spec/frontend/test_setup.js

@@ -2,6 +2,7 @@ import Vue from 'vue';
 import Translate from '~/vue_shared/translate';
 import axios from '~/lib/utils/axios_utils';
 import { initializeTestTimeout } from './helpers/timeout';
+import { getJSONFixture, loadHTMLFixture, setHTMLFixture } from './helpers/fixtures';
 
 // wait for pending setTimeout()s
 afterEach(() => {
@@ -32,3 +33,11 @@ Object.defineProperty(global.Element.prototype, 'innerText', {
   },
   configurable: true, // make it so that it doesn't blow chunks on re-running tests with things like --watch
 });
+
+// convenience wrapper for migration from Karma
+Object.assign(global, {
+  loadFixtures: loadHTMLFixture,
+  loadJSONFixtures: getJSONFixture,
+  preloadFixtures() {},
+  setFixtures: setHTMLFixture,
+});