Add unit and integration jest.config files

**Why?**
To write [FE integration tests][1], we will need
to have two related but different environments.
The best way to do this is with two configs and
a base config.

[1]: https://docs.gitlab.com/ee/development/testing_guide/testing_levels.html#frontend-integration-tests

.eslintignore

@@ -9,6 +9,6 @@
 /scripts/
 /tmp/
 /vendor/
-jest.config.js
+jest.config.*.js
 karma.config.js
 webpack.config.js

jest.config.base.js

+const IS_EE = require('./config/helpers/is_ee_env');
+
+module.exports = path => {
+  const reporters = ['default'];
+
+  // To have consistent date time parsing both in local and CI environments we set
+  // the timezone of the Node process. https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/27738
+  process.env.TZ = 'GMT';
+
+  if (process.env.CI) {
+    reporters.push([
+      'jest-junit',
+      {
+        output: './junit_jest.xml',
+      },
+    ]);
+  }
+
+  const glob = `${path}/**/*_spec.js`;
+  let testMatch = [`<rootDir>/${glob}`];
+  if (IS_EE) {
+    testMatch.push(`<rootDir>/ee/${glob}`);
+  }
+
+  // workaround for eslint-import-resolver-jest only resolving in test files
+  // see https://github.com/JoinColony/eslint-import-resolver-jest#note
+  const { filename: parentModuleName } = module.parent;
+  const isESLint = parentModuleName && parentModuleName.includes('/eslint-import-resolver-jest/');
+  if (isESLint) {
+    testMatch = testMatch.map(path => path.replace('_spec.js', ''));
+  }
+
+  const moduleNameMapper = {
+    '^~(/.*)$': '<rootDir>/app/assets/javascripts$1',
+    '^ee_component(/.*)$':
+      '<rootDir>/app/assets/javascripts/vue_shared/components/empty_component.js',
+    '^ee_else_ce(/.*)$': '<rootDir>/app/assets/javascripts$1',
+    '^helpers(/.*)$': '<rootDir>/spec/frontend/helpers$1',
+    '^vendor(/.*)$': '<rootDir>/vendor/assets/javascripts$1',
+    '\\.(jpg|jpeg|png|svg|css)$': '<rootDir>/spec/frontend/__mocks__/file_mock.js',
+    'emojis(/.*).json': '<rootDir>/fixtures/emojis$1.json',
+    '^spec/test_constants$': '<rootDir>/spec/frontend/helpers/test_constants',
+    '^jest/(.*)$': '<rootDir>/spec/frontend/$1',
+  };
+
+  const collectCoverageFrom = ['<rootDir>/app/assets/javascripts/**/*.{js,vue}'];
+
+  if (IS_EE) {
+    const rootDirEE = '<rootDir>/ee/app/assets/javascripts$1';
+    Object.assign(moduleNameMapper, {
+      '^ee(/.*)$': rootDirEE,
+      '^ee_component(/.*)$': rootDirEE,
+      '^ee_else_ce(/.*)$': rootDirEE,
+      '^ee_jest/(.*)$': '<rootDir>/ee/spec/frontend/$1',
+    });
+
+    collectCoverageFrom.push(rootDirEE.replace('$1', '/**/*.{js,vue}'));
+  }
+
+  const coverageDirectory = () => {
+    if (process.env.CI_NODE_INDEX && process.env.CI_NODE_TOTAL) {
+      return `<rootDir>/coverage-frontend/jest-${process.env.CI_NODE_INDEX}-${process.env.CI_NODE_TOTAL}`;
+    }
+
+    return '<rootDir>/coverage-frontend/';
+  };
+
+  return {
+    clearMocks: true,
+    testMatch,
+    moduleFileExtensions: ['js', 'json', 'vue'],
+    moduleNameMapper,
+    collectCoverageFrom,
+    coverageDirectory: coverageDirectory(),
+    coverageReporters: ['json', 'lcov', 'text-summary', 'clover'],
+    cacheDirectory: '<rootDir>/tmp/cache/jest',
+    modulePathIgnorePatterns: ['<rootDir>/.yarn-cache/'],
+    reporters,
+    setupFilesAfterEnv: ['<rootDir>/spec/frontend/test_setup.js', 'jest-canvas-mock'],
+    restoreMocks: true,
+    transform: {
+      '^.+\\.(gql|graphql)$': 'jest-transform-graphql',
+      '^.+\\.js$': 'babel-jest',
+      '^.+\\.vue$': 'vue-jest',
+    },
+    transformIgnorePatterns: ['node_modules/(?!(@gitlab/ui|bootstrap-vue|three|monaco-editor)/)'],
+    timers: 'fake',
+    testEnvironment: '<rootDir>/spec/frontend/environment.js',
+    testEnvironmentOptions: {
+      IS_EE,
+    },
+  };
+};

jest.config.integration.js

+const baseConfig = require('./jest.config.base');
+
+module.exports = {
+  ...baseConfig('spec/frontend_integration'),
+};

jest.config.js

-const IS_EE = require('./config/helpers/is_ee_env');
-
-const reporters = ['default'];
-
-// To have consistent date time parsing both in local and CI environments we set
-// the timezone of the Node process. https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/27738
-process.env.TZ = 'GMT';
-
-if (process.env.CI) {
-  reporters.push([
-    'jest-junit',
-    {
-      output: './junit_jest.xml',
-    },
-  ]);
-}
-
-let testMatch = ['<rootDir>/spec/frontend/**/*_spec.js'];
-if (IS_EE) {
-  testMatch.push('<rootDir>/ee/spec/frontend/**/*_spec.js');
-}
-
-// workaround for eslint-import-resolver-jest only resolving in test files
-// see https://github.com/JoinColony/eslint-import-resolver-jest#note
-const { filename: parentModuleName } = module.parent;
-const isESLint = parentModuleName && parentModuleName.includes('/eslint-import-resolver-jest/');
-if (isESLint) {
-  testMatch = testMatch.map(path => path.replace('_spec.js', ''));
-}
-
-const moduleNameMapper = {
-  '^~(/.*)$': '<rootDir>/app/assets/javascripts$1',
-  '^ee_component(/.*)$':
-    '<rootDir>/app/assets/javascripts/vue_shared/components/empty_component.js',
-  '^ee_else_ce(/.*)$': '<rootDir>/app/assets/javascripts$1',
-  '^helpers(/.*)$': '<rootDir>/spec/frontend/helpers$1',
-  '^vendor(/.*)$': '<rootDir>/vendor/assets/javascripts$1',
-  '\\.(jpg|jpeg|png|svg|css)$': '<rootDir>/spec/frontend/__mocks__/file_mock.js',
-  'emojis(/.*).json': '<rootDir>/fixtures/emojis$1.json',
-  '^spec/test_constants$': '<rootDir>/spec/frontend/helpers/test_constants',
-  '^jest/(.*)$': '<rootDir>/spec/frontend/$1',
-};
-
-const collectCoverageFrom = ['<rootDir>/app/assets/javascripts/**/*.{js,vue}'];
-
-if (IS_EE) {
-  const rootDirEE = '<rootDir>/ee/app/assets/javascripts$1';
-  Object.assign(moduleNameMapper, {
-    '^ee(/.*)$': rootDirEE,
-    '^ee_component(/.*)$': rootDirEE,
-    '^ee_else_ce(/.*)$': rootDirEE,
-    '^ee_jest/(.*)$': '<rootDir>/ee/spec/frontend/$1',
-  });
-
-  collectCoverageFrom.push(rootDirEE.replace('$1', '/**/*.{js,vue}'));
-}
-
-const coverageDirectory = () => {
-  if (process.env.CI_NODE_INDEX && process.env.CI_NODE_TOTAL) {
-    return `<rootDir>/coverage-frontend/jest-${process.env.CI_NODE_INDEX}-${process.env.CI_NODE_TOTAL}`;
-  }
-
-  return '<rootDir>/coverage-frontend/';
-};
-
-// eslint-disable-next-line import/no-commonjs
-module.exports = {
-  clearMocks: true,
-  testMatch,
-  moduleFileExtensions: ['js', 'json', 'vue'],
-  moduleNameMapper,
-  collectCoverageFrom,
-  coverageDirectory: coverageDirectory(),
-  coverageReporters: ['json', 'lcov', 'text-summary', 'clover'],
-  cacheDirectory: '<rootDir>/tmp/cache/jest',
-  modulePathIgnorePatterns: ['<rootDir>/.yarn-cache/'],
-  reporters,
-  setupFilesAfterEnv: ['<rootDir>/spec/frontend/test_setup.js', 'jest-canvas-mock'],
-  restoreMocks: true,
-  transform: {
-    '^.+\\.(gql|graphql)$': 'jest-transform-graphql',
-    '^.+\\.js$': 'babel-jest',
-    '^.+\\.vue$': 'vue-jest',
-  },
-  transformIgnorePatterns: ['node_modules/(?!(@gitlab/ui|bootstrap-vue|three|monaco-editor)/)'],
-  timers: 'fake',
-  testEnvironment: '<rootDir>/spec/frontend/environment.js',
-  testEnvironmentOptions: {
-    IS_EE,
-  },
-};
-
-const karmaTestFile = process.argv.find(arg => arg.includes('spec/javascripts/'));
-if (karmaTestFile) {
-  console.error(`
-Files in spec/javascripts/ and ee/spec/javascripts need to be run with Karma.
-Please use the following command instead:
-
-yarn karma -f ${karmaTestFile}
-
-`);
-  process.exit(1);
-}

jest.config.unit.js

+const baseConfig = require('./jest.config.base');
+
+module.exports = {
+  ...baseConfig('spec/frontend'),
+};
+
+const karmaTestFile = process.argv.find(arg => arg.includes('spec/javascripts/'));
+if (karmaTestFile) {
+  console.error(`
+Files in spec/javascripts/ and ee/spec/javascripts need to be run with Karma.
+Please use the following command instead:
+
+yarn karma -f ${karmaTestFile}
+
+`);
+  process.exit(1);
+}

package.json

@@ -10,7 +10,7 @@
     "eslint-report": "eslint --max-warnings 0 --ext .js,.vue --format html --output-file ./eslint-report.html --no-inline-config .",
     "file-coverage": "scripts/frontend/file_test_coverage.js",
     "prejest": "yarn check-dependencies",
-    "jest": "jest",
+    "jest": "jest --config jest.config.unit.js",
     "jest-debug": "node --inspect-brk node_modules/.bin/jest --runInBand",
     "jsdoc": "jsdoc -c config/jsdocs.config.js",
     "prekarma": "yarn check-dependencies",

spec/frontend/.eslintrc.yml

@@ -10,7 +10,7 @@ settings:
     - path
   import/resolver:
     jest:
-      jestConfigFile: 'jest.config.js'
+      jestConfigFile: 'jest.config.unit.js'
 globals:
   getJSONFixture: false
   loadFixtures: false