Guide to Testing Node.js Applications with Jest and TypeScript

Topics covered

Testing Principles: Understand the importance of testing and distinctions between unit, integration, and end-to-end testing.

Writing Your First Test: Create a simple function and write a test using Jest and TypeScript.

Test Organization and Isolation: Organize tests using describe blocks and ensure test isolation.

Arranging, Acting, and Asserting: Follow the AAA pattern for test cases.

Testing Asynchronous Code: Handle asynchronous operations with Jest's capabilities.

[peterbarrow]

Thanks for the solid video tutorial! Found it very helpful, and the demonstration of Arrange, Act, Assert was a good frame of mind.

[kaygeea]

I’m just about to start implementing testing for my project and this was a good introduction. I like the triple AAA arrangement.

A question at 21:02: when performing the async test and saying ‘expect(data).toEqual()’ can you pass a typescript interface or type as a representation of the expected return, instead of the actual object?