Add getJSONFixture() helper to Jest

jest.config.js

@@ -18,7 +18,6 @@ module.exports = {
   moduleNameMapper: {
     '^~(.*)$': '<rootDir>/app/assets/javascripts$1',
     '^ee(.*)$': '<rootDir>/ee/app/assets/javascripts$1',
-    '^fixtures(.*)$': '<rootDir>/spec/javascripts/fixtures$1',
     '^helpers(.*)$': '<rootDir>/spec/frontend/helpers$1',
     '^vendor(.*)$': '<rootDir>/vendor/assets/javascripts$1',
     '\\.(jpg|jpeg|png|svg)$': '<rootDir>/spec/frontend/__mocks__/file_mock.js',

spec/frontend/gfm_auto_complete_spec.js

@@ -8,11 +8,12 @@ import 'vendor/jquery.atwho';
 
 import { TEST_HOST } from 'helpers/test_constants';
 import { setTestTimeout } from 'helpers/timeout';
-
-import labelsFixture from 'fixtures/autocomplete_sources/labels.json'; // eslint-disable-line import/no-unresolved
+import { getJSONFixture } from 'helpers/fixtures';
 
 setTestTimeout(500);
 
+const labelsFixture = getJSONFixture('autocomplete_sources/labels.json');
+
 describe('GfmAutoComplete', () => {
   const gfmAutoCompleteCallbacks = GfmAutoComplete.prototype.getDefaultCallbacks.call({
     fetchData: () => {},

spec/frontend/helpers/fixtures.js

+/* eslint-disable import/prefer-default-export, global-require, import/no-dynamic-require */
+
+import fs from 'fs';
+import path from 'path';
+
+// jest-util is part of Jest
+// eslint-disable-next-line import/no-extraneous-dependencies
+import { ErrorWithStack } from 'jest-util';
+
+const fixturesBasePath = path.join(process.cwd(), 'spec', 'javascripts', 'fixtures');
+
+export function getJSONFixture(relativePath, ee = false) {
+  const absolutePath = path.join(fixturesBasePath, ee ? 'ee' : '', relativePath);
+  if (!fs.existsSync(absolutePath)) {
+    throw new ErrorWithStack(
+      `Fixture file ${relativePath} does not exist.
+
+Did you run bin/rake karma:fixtures?`,
+      getJSONFixture,
+    );
+  }
+
+  return require(absolutePath);
+}