Vitest Learning Playground

Note

This repository is for learning and experimenting with vitest

This is a demo project that showcases examples and serves as a guide to implement vitest with typescript.

References

• Vitest - Documentation
• Rapid Testing with Vitest - Course
• Vitest Basic Example - Github codebase
• Web.dev Learn Testing - Course

Scripts

npm run test # Run all tests on watch mode
npm run test sum # Run a specific test

Used Vitest API

test/sum.test.ts

• Getting Started
• test()
• expect()
• expect().toEqual()

tests/merge.test.ts

• describe()
• expect().toThrowError()

tests/spying.test.ts

• Spying/Mocking functions
• vi.spyOn()
• expect().toHaveBeenCalledTimes()
• expect().toHaveBeenCalledWith

tests/mock.test.ts

• Mocking
• Mocking - File System
• vi.mock()
• `vi.hoisted()
• vi.resetModules()

Warning

Vitest will not mock modules that were imported inside a setup file because they are cached by the time a test file is running. You can call vi.resetModules() inside vi.hoisted to clear all module caches before running a test file.

https://vitest.dev/api/vi.html#vi-mock

tests/time.test.ts

• vi.setSystemTime()
• expect().toBe()

tests/timer.test.ts

• Mocking Timers
• vi.useFakeTimers()
• vi.advanceTimersByTime()
• vi.advanceTimersToNextTimer()

tests/network.test.ts

• Request
• Setup Files
• expect().toMatchInlineSnapshot()
• vi.stubGlobal()
• MSW - Node.js integration
• MSW - Intercepting requests
• MSW - setupServer()
• MSW - http.get()
• MSW - http.json()