Upgrade Jest and use TS for Jest config (#97)

v27 is the latest version of Jest and introduces these major changes:

* `node` is now the default environment instead of `jsdom`. This
  results in faster runtimes.
* The runner has been completely rewritten as `jest-circus` which is
  also the default, replacing `jest-jasmine2`.
  * This should have no impact on us as we don't rely on any
    Jasmine-specific APIs, but is nice to know.
* The "modern" version of Fake Timers (enabled via
  `jest.useFakeTimers("modern")`) is now the default.

More info here: <https://jestjs.io/blog/2021/05/25/jest-27>

Additionally, to ensure that we make use of all of the latest and
greatest, this PR regenerates the Jest config file (as
`jest.config.ts`). This has the added improvement that each option is
now commented so we know exactly what each one does.

.eslintrc.js

@@ -21,6 +21,14 @@ module.exports = {
       files: ['*.test.ts', '*.test.js'],
       extends: ['@metamask/eslint-config-jest'],
     },
+
+    {
+      files: ['jest.config.ts'],
+      rules: {
+        // TODO: Migrate to our shared config
+        'import/no-anonymous-default-export': 'off',
+      },
+    },
   ],
 
   ignorePatterns: ['!.eslintrc.js', '!.prettierrc.js', 'dist/'],

jest.config.ts

@@ -0,0 +1,204 @@
+/*
+ * For a detailed explanation regarding each configuration property and type check, visit:
+ * https://jestjs.io/docs/configuration
+ */
+
+export default {
+  // All imported modules in your tests should be mocked automatically
+  // automock: false,
+
+  // Stop running tests after `n` failures
+  // bail: 0,
+
+  // The directory where Jest should store its cached dependency information
+  // cacheDirectory: "/private/var/folders/fk/c3y07g0576j8_2s9m01pk4qw0000gn/T/jest_dx",
+
+  // Automatically clear mock calls, instances and results before every test.
+  // This does not remove any mock implementation that may have been provided,
+  // so we disable it.
+  // clearMocks: true,
+
+  // Indicates whether the coverage information should be collected while executing the test
+  collectCoverage: true,
+
+  // An array of glob patterns indicating a set of files for which coverage information should be collected
+  collectCoverageFrom: ['./src/**/*.ts'],
+
+  // The directory where Jest should output its coverage files
+  coverageDirectory: 'coverage',
+
+  // An array of regexp pattern strings used to skip coverage collection
+  // coveragePathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // Indicates which provider should be used to instrument code for coverage
+  coverageProvider: 'v8',
+
+  // A list of reporter names that Jest uses when writing coverage reports
+  coverageReporters: ['text', 'html'],
+
+  // An object that configures minimum threshold enforcement for coverage results
+  coverageThreshold: {
+    global: {
+      branches: 100,
+      functions: 100,
+      lines: 100,
+      statements: 100,
+    },
+  },
+
+  // A path to a custom dependency extractor
+  // dependencyExtractor: undefined,
+
+  // Make calling deprecated APIs throw helpful error messages
+  // errorOnDeprecated: false,
+
+  // Force coverage collection from ignored files using an array of glob patterns
+  // forceCoverageMatch: [],
+
+  // A path to a module which exports an async function that is triggered once before all test suites
+  // globalSetup: undefined,
+
+  // A path to a module which exports an async function that is triggered once after all test suites
+  // globalTeardown: undefined,
+
+  // A set of global variables that need to be available in all test environments
+  // globals: {},
+
+  // The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
+  // maxWorkers: "50%",
+
+  // An array of directory names to be searched recursively up from the requiring module's location
+  // moduleDirectories: [
+  //   "node_modules"
+  // ],
+
+  // An array of file extensions your modules use
+  // moduleFileExtensions: [
+  //   "js",
+  //   "jsx",
+  //   "ts",
+  //   "tsx",
+  //   "json",
+  //   "node"
+  // ],
+
+  // A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
+  // moduleNameMapper: {},
+
+  // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+  // modulePathIgnorePatterns: [],
+
+  // Activates notifications for test results
+  // notify: false,
+
+  // An enum that specifies notification mode. Requires { notify: true }
+  // notifyMode: "failure-change",
+
+  // A preset that is used as a base for Jest's configuration
+  preset: 'ts-jest',
+
+  // Run tests from one or more projects
+  // projects: undefined,
+
+  // Use this configuration option to add custom reporters to Jest
+  // reporters: undefined,
+
+  // "resetMocks" resets all mocks, including mocked modules, to jest.fn(),
+  // between each test case.
+  resetMocks: true,
+
+  // Reset the module registry before running each individual test
+  // resetModules: false,
+
+  // A path to a custom resolver
+  // resolver: undefined,
+
+  // "restoreMocks" restores all mocks created using jest.spyOn to their
+  // original implementations, between each test. It does not affect mocked
+  // modules.
+  restoreMocks: true,
+
+  // The root directory that Jest should scan for tests and modules within
+  // rootDir: undefined,
+
+  // A list of paths to directories that Jest should use to search for files in
+  // roots: [
+  //   "<rootDir>"
+  // ],
+
+  // Allows you to use a custom runner instead of Jest's default test runner
+  // runner: "jest-runner",
+
+  // The paths to modules that run some code to configure or set up the testing environment before each test
+  // setupFiles: [],
+
+  // A list of paths to modules that run some code to configure or set up the testing framework before each test
+  // setupFilesAfterEnv: [],
+
+  // The number of seconds after which a test is considered as slow and reported as such in the results.
+  // slowTestThreshold: 5,
+
+  // A list of paths to snapshot serializer modules Jest should use for snapshot testing
+  // snapshotSerializers: [],
+
+  // The test environment that will be used for testing
+  // testEnvironment: "jest-environment-node",
+
+  // Options that will be passed to the testEnvironment
+  // testEnvironmentOptions: {},
+
+  // Adds a location field to test results
+  // testLocationInResults: false,
+
+  // The glob patterns Jest uses to detect test files
+  // testMatch: [
+  //   "**/__tests__/**/*.[jt]s?(x)",
+  //   "**/?(*.)+(spec|test).[tj]s?(x)"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+  // testPathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // The regexp pattern or array of patterns that Jest uses to detect test files
+  // testRegex: [],
+
+  // This option allows the use of a custom results processor
+  // testResultsProcessor: undefined,
+
+  // This option allows use of a custom test runner
+  // testRunner: "jest-circus/runner",
+
+  // Reduce the default test timeout from 5s to 2.5s
+  testTimeout: 2500,
+
+  // This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
+  // testURL: "http://localhost",
+
+  // Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
+  // timers: "real",
+
+  // A map from regular expressions to paths to transformers
+  // transform: undefined,
+
+  // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+  // transformIgnorePatterns: [
+  //   "/node_modules/",
+  //   "\\.pnp\\.[^\\/]+$"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+  // unmockedModulePathPatterns: undefined,
+
+  // Indicates whether each individual test should be reported during the run
+  // verbose: undefined,
+
+  // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+  // watchPathIgnorePatterns: [],
+
+  // Whether to use watchman for file crawling
+  // watchman: true,
+};

package.json

@@ -31,6 +31,7 @@
     "@metamask/eslint-config-nodejs": "^9.0.0",
     "@metamask/eslint-config-typescript": "^9.0.1",
     "@types/jest": "^26.0.13",
+    "@types/node": "^17.0.23",
     "@typescript-eslint/eslint-plugin": "^4.21.0",
     "@typescript-eslint/parser": "^4.21.0",
     "eslint": "^7.23.0",
@@ -40,11 +41,12 @@
     "eslint-plugin-jsdoc": "^36.1.0",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-prettier": "^3.3.1",
-    "jest": "^26.4.2",
+    "jest": "^27.5.1",
     "prettier": "^2.2.1",
     "prettier-plugin-packagejson": "^2.2.11",
     "rimraf": "^3.0.2",
-    "ts-jest": "^26.3.0",
+    "ts-jest": "^27.1.4",
+    "ts-node": "^10.7.0",
     "typescript": "^4.2.4"
   },
   "engines": {