refactor(checkbox): Add Jasmine test for checkbox foundation. (#5299)

- Add checkbox foundation test using Jasmine framework (converted from existing Mocha test). Does not delete Mocha test yet; this will be done in a follow-up PR.
- Set up Karma config such that `npm run test:jasmineunit` runs Karma/Jasmine unit tests, `npm run test:mochaunit` runs Karma/Mocha unit tests, and `npm run test:unit` runs both.
- Set up code coverage via `karma-typescript`/`istanbul`. Thresholds are lowered for now since Jasmine tests do not cover component tests yet, which were increasing the coverage percentage.

karma.conf.js

@@ -26,6 +26,16 @@ const webpackConfig = require('./webpack.config')[1];
 
 const USING_TRAVISCI = Boolean(process.env.TRAVIS);
 const USING_SL = Boolean(process.env.SAUCE_USERNAME && process.env.SAUCE_ACCESS_KEY);
+// If true, runs new suite of Jasmine foundation unit tests.
+// Otherwise, runs old Mocha unit tests.
+const USE_JASMINE = Boolean(process.env.USE_JASMINE);
+
+// Files to include in Jasmine tests.
+const FILES_TO_USE = [
+  'packages/*/!(node_modules)/**/!(*.d).ts',
+  'packages/*/!(*.d).ts',
+  'testing/**/*.ts',
+];
 
 const HEADLESS_LAUNCHERS = {
   /** See https://github.com/travis-ci/travis-ci/issues/8836#issuecomment-348248951 */
@@ -63,79 +73,125 @@ const istanbulInstrumenterLoader = {
   include: path.resolve('./packages'),
 };
 
-module.exports = function(config) {
-  config.set({
-    basePath: '',
-    // Refer https://github.com/karma-runner/karma-mocha
-    frameworks: ['mocha'],
-    files: [
-      // Refer https://github.com/babel/karma-babel-preprocessor
-      'node_modules/@babel/polyfill/dist/polyfill.js',
-      'test/unit/index.js',
-    ],
-    preprocessors: {
-      'test/unit/index.js': ['webpack', 'sourcemap'],
+const mochaConfig = {
+  basePath: '',
+  // Refer https://github.com/karma-runner/karma-mocha
+  frameworks: ['mocha'],
+  files: [
+    // Refer https://github.com/babel/karma-babel-preprocessor
+    'node_modules/@babel/polyfill/dist/polyfill.js',
+    'test/unit/index.js',
+  ],
+  preprocessors: {
+    'test/unit/index.js': ['webpack', 'sourcemap'],
+  },
+  reporters: ['progress', 'coverage-istanbul'],
+
+  coverageIstanbulReporter: {
+    'dir': 'coverage',
+    'reports': ['html', 'lcovonly', 'json'],
+    'report-config': {
+      lcovonly: {subdir: '.'},
+      json: {subdir: '.', file: 'coverage.json'},
+    },
+    // Set 'emitWarning = true' to NOT fail tests if the thresholds are not met
+    'emitWarning': false,
+    'thresholds': {
+      statements: 95,
+      branches: 95,
+      lines: 95,
+      functions: 95,
+    },
+  },
+
+  client: {
+    mocha: {
+      reporter: 'html',
+      ui: 'qunit',
+
+      // Number of milliseconds to wait for an individual `test(...)` function to complete.
+      // The default is 2000.
+      timeout: 10000,
+    },
+  },
+
+  webpackMiddleware: {
+    noInfo: true,
+    stats: 'minimal',
+  },
+};
+
+const jasmineConfig = {
+  basePath: '',
+  files: FILES_TO_USE,
+  frameworks: ['jasmine', 'karma-typescript'],
+  karmaTypescriptConfig: {
+    coverageOptions: {
+      threshold: {
+        global: {
+          // TODO: Raise threshold to at least 90% after more tests have been migrated.
+          statements: 80,
+          branches: 80,
+          functions: 50,
+          lines: 80,
+          excludes: [
+            'testing/**/*.ts',
+            'packages/!(mdc-checkbox)/**/*',
+            'packages/**/component.ts', // Jasmine tests cover foundation/adapter only.
+          ],
+        },
+      },
+    },
+    reports: {
+      html: 'coverage',
+      lcovonly: 'coverage',
+      json: {
+        directory: 'coverage',
+        filename: 'coverage.json',
+      },
     },
-    reporters: ['progress', 'coverage-istanbul'],
+    tsconfig: './tsconfig.json',
+  },
+  preprocessors: FILES_TO_USE.reduce((obj, file) => {
+    obj[file] = 'karma-typescript';
+    return obj;
+  }, {}),
+  reporters: ['progress', 'karma-typescript'],
+};
+
+module.exports = function(config) {
+  config.set(Object.assign(USE_JASMINE ? jasmineConfig : mochaConfig, {
+    logLevel: config.LOG_INFO,
     port: 9876,
     colors: true,
-    logLevel: config.LOG_INFO,
     browsers: browsers,
     browserDisconnectTimeout: 40000,
     browserNoActivityTimeout: 120000,
     captureTimeout: 240000,
     concurrency: USING_SL ? 4 : Infinity,
     customLaunchers: customLaunchers,
+  }));
 
-    coverageIstanbulReporter: {
-      'dir': 'coverage',
-      'reports': ['html', 'lcovonly', 'json'],
-      'report-config': {
-        lcovonly: {subdir: '.'},
-        json: {subdir: '.', file: 'coverage.json'},
-      },
-      // 'emitWarning' causes the tests to fail if the thresholds are not met
-      'emitWarning': false,
-      'thresholds': {
-        statements: 95,
-        branches: 95,
-        lines: 95,
-        functions: 95,
-      },
-    },
-
-    client: {
-      mocha: {
-        reporter: 'html',
-        ui: 'qunit',
-
-        // Number of milliseconds to wait for an individual `test(...)` function to complete.
-        // The default is 2000.
-        timeout: 10000,
-      },
-    },
-
-    // Refer https://github.com/webpack-contrib/karma-webpack
-    webpack: Object.assign({}, webpackConfig, {
-      plugins: [], // Exclude UglifyJs plugin from test build.
-      mode: 'development',
-      module: Object.assign({}, webpackConfig.module, {
-        // Cover source files when not debugging tests. Otherwise, omit coverage instrumenting to get
-        // uncluttered source maps.
-        rules: webpackConfig.module.rules.concat(config.singleRun ? [Object.assign({
-          enforce: 'post',
-          test: /\.ts$/,
-        }, istanbulInstrumenterLoader), Object.assign({
-          test: /\.js$/,
-        }, istanbulInstrumenterLoader)] : []),
+  if (!USE_JASMINE) {
+    // Need to set webpack here rather than in `mochaConfig` to read `config.singleRun`.
+    config.set({
+      // Refer https://github.com/webpack-contrib/karma-webpack
+      webpack: Object.assign({}, webpackConfig, {
+        plugins: [], // Exclude UglifyJs plugin from test build.
+        mode: 'development',
+        module: Object.assign({}, webpackConfig.module, {
+          // Cover source files when not debugging tests. Otherwise, omit coverage instrumenting to get
+          // uncluttered source maps.
+          rules: webpackConfig.module.rules.concat(config.singleRun ? [Object.assign({
+            enforce: 'post',
+            test: /\.ts$/,
+          }, istanbulInstrumenterLoader), Object.assign({
+            test: /\.js$/,
+          }, istanbulInstrumenterLoader)] : []),
+        }),
       }),
-    }),
-
-    webpackMiddleware: {
-      noInfo: true,
-      stats: 'minimal',
-    },
-  });
+    });
+  }
 
   if (USING_SL) {
     const sauceLabsConfig = {