Test environment

If you look at setup-jest.js, what we're doing here is we're adding globals required by Angular. With the included Angular zone patch we also make sure Jest test methods run in Zone context. Then we initialize the Angular testing environment like normal.

While setup-jest.js above is for running Jest with CommonJS mode, we also provide setup-jest.mjs to run with ESM mode.

Configure test environment

When creating Angular test environment with TestBed, it is possible to specify the testEnvironmentOptions via globalThis in the Jest setup file. For example:

// setup-test.ts
globalThis.ngJest = {
  testEnvironmentOptions: {
    teardown: {
      destroyAfterEach: false,
      rethrowErrors: true,
    },
    errorOnUnknownElements: true,
    errorOnUnknownProperties: true,
  },
};

import 'jest-preset-angular/setup-jest';

jest-preset-angular will look at globalThis.ngJest and pass the correct TestEnvironmentOptions object to TestBed.