Jasmine: Karma browser tests and migrating to Jest

Deep reference for jasmine-tests SKILL.md. Consult when running Jasmine specs in a real browser via Karma (the legacy Angular CLI default), or when moving a Jasmine suite to Jest.

Karma integration (browser tests)

For browser-environment tests (legacy Angular CLI default):

npm install --save-dev karma karma-jasmine karma-chrome-launcher

karma.conf.js:

module.exports = function(config) {
  config.set({
    frameworks: ['jasmine'],
    files: ['src/**/*.spec.js'],
    browsers: ['ChromeHeadless'],
    singleRun: true,
    reporters: ['progress', 'junit'],
  });
};

npx karma start

Important migration note: Karma is in maintenance-only mode as of 2023; AngularJS reached end-of-life Jan 2022; new Angular projects use Jest or Vitest. Karma + Jasmine setups are explicitly legacy.

Migration to Jest path

Jest's API is mostly compatible with Jasmine - typical migration steps:

1. Replace spyOn().and.returnValue() with jest.spyOn().mockReturnValue()
2. Replace jasmine.createSpy() with jest.fn()
3. Replace jasmine.createSpyObj() with manual jest.fn() per method
4. Replace expect().toBeNan() with expect(Number.isNaN()).toBe(true) (matcher renamed)
5. Add jest.config.js with appropriate testMatch
6. Drop Karma if used (Jest handles its own jsdom env)

For automated migration: jest-codemods package handles ~80% of the syntax transformations.