Move to Jest

- Remove mocha/chai/nyc dependencies
- Add jest + ts-jest dependencies
- Update eslintrc for jest
- Move mocha/nyc configs to jest config
- Add custom environment to fix Uint8Array issues
  (jestjs/jest#4422)
- Add custom reporters for cleaner output
- Update test files
- Update npm scripts
- Break up e2e tests into separate files for concurrency

.eslintrc.js

@@ -8,7 +8,7 @@ module.exports = {
     sourceType: 'module',  // Allows for the use of imports
   },
   env: {
-    'mocha': true,
+    'jest': true,
   },
   parserOptions: {
     project: './tsconfig.build.json'

.gitignore

@@ -44,8 +44,6 @@ lib-cov
 
 # Coverage directory used by tools like istanbul
 coverage
-
-# nyc test coverage
 .nyc_output
 
 # Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)

jest.config.js

@@ -0,0 +1,19 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: './jest/custom-environment',
+  verbose: false,
+  reporters: [
+    './jest/log-on-fail-reporter.js',
+    './jest/summary-reporter.js',
+  ],
+  setupFilesAfterEnv: ['./jest.setup.js'],
+  collectCoverage: false,
+  collectCoverageFrom: [
+    '**/src/**/*.ts',
+    '!**/*.d.ts',
+    '!**/index.ts',
+  ],
+  coveragePathIgnorePatterns: [
+    '<rootDir>/packages/cashc/src/grammar/',
+  ],
+};

jest.setup.js

@@ -0,0 +1 @@
+jest.setTimeout(25000);

jest/custom-environment.js

@@ -0,0 +1,32 @@
+// my-custom-environment
+const NodeEnvironment = require('jest-environment-node');
+
+class CustomEnvironment extends NodeEnvironment {
+  constructor(config, context) {
+    Object.assign(
+      config.globals,
+      {
+        Uint8Array,
+        ArrayBuffer,
+      },
+    );
+    super(config, context);
+    this.testPath = context.testPath;
+    this.docblockPragmas = context.docblockPragmas;
+  }
+
+
+  async setup() {
+    await super.setup();
+  }
+
+  async teardown() {
+    await super.teardown();
+  }
+
+  runScript(script) {
+    return super.runScript(script);
+  }
+}
+
+module.exports = CustomEnvironment;

jest/log-on-fail-reporter.js

@@ -0,0 +1,29 @@
+const chalk = require('chalk');
+const { getConsoleOutput } = require('jest-util');
+const DefaultReporter = require('@jest/reporters/build/default_reporter').default;
+const getResultHeader = require('@jest/reporters/build/get_result_header').default;
+
+const TITLE_BULLET = chalk.bold('\u25cf ');
+
+// This Jest reporter does not output any console.log except when the tests are
+// failing, see: https://github.com/mozilla/addons-frontend/issues/2980.
+class LogOnFailReporter extends DefaultReporter {
+  printTestFileHeader(testPath, config, result) {
+    this.log(getResultHeader(result, this._globalConfig, config));
+
+    const consoleBuffer = result.console;
+    const testFailed = result.numFailingTests > 0;
+
+    if (testFailed && consoleBuffer && consoleBuffer.length) {
+      this.log(
+        `  ${TITLE_BULLET}Console\n\n${getConsoleOutput(
+          config.cwd,
+          !!this._globalConfig.verbose,
+          consoleBuffer,
+        )}`,
+      );
+    }
+  }
+}
+
+module.exports = LogOnFailReporter;

jest/summary-reporter.js

@@ -0,0 +1,3 @@
+const { SummaryReporter } = require('@jest/reporters');
+
+module.exports = SummaryReporter;