Angular with Jest Testing

Jest is a painless JavaScript testing platform.

• Jest is a testing platform, widely adapted by many large companies and swiftly adopted by the React community.
• Sits on top of Jasmine, so the API is nearly identical.
• Focuses on Developer Experience (speed and ease of use is the first priority.)
• Provides meaningful error messages.
• Runs on Continuous Integration servers without extra tooling (abstracting the DOM with jsdom library.)
• Provides code coverage out of the box.
• Integrates with Babel and TypeScript seamlessly.

And what’s most important is that it provides a smart, immersive watch mode. The watch mode runs only tests affected by git file changes — it also runs failed tests first and is able to bail on first error so the feedback loop is ~10x faster than with Karma, depending on test suite size.

Add to application

yarn add --dev jest jest-preset-angular @types/jest

where:

• jest — Jest testing platform
• jest-preset-angular — configuration preset with common settings setup for you
• @types/jest — Jest typings