前端 测试
Facebook 推出的基于 Jasmine 的 JavaScript 测试框架
2019-11-12 我要评论 3 我要收藏

Jest Build Status

Painless JavaScript Unit Testing

  • Familiar Approach: Built on top of the Jasmine test framework, using familiar expect(value).toBe(other) assertions

  • Mock by Default: Automatically mocks CommonJS modules returned by require(), making most existing code testable

  • Short Feedback Loop: DOM APIs are mocked and tests run in parallel via a small node.js command line utility

Getting Started

Check out the Getting Started tutorial. It's pretty simple!


The jest object

Mock functions

Config options

Globally injected variables

  • afterEach(fn)
  • beforeEach(fn)
  • describe(name, fn)
  • it(name, fn)
  • it.only(name, fn) executes only this test. Useful when investigating a failure
  • jest
  • pit(name, fn) helper for promises
  • require(module)
  • require.requireActual(module)
  • xdescribe(name, fn)
  • xit(name, fn)


  • .not inverse the next comparison
  • .toThrow(?message)
  • .toBe(value) comparison using ===
  • .toEqual(value) deep comparison. Use jasmine.any(type) to be softer
  • .toBeFalsy()
  • .toBeTruthy()
  • .toBeNull()
  • .toBeUndefined()
  • .toBeDefined()
  • .toMatch(regexp)
  • .toContain(string)
  • .toBeCloseTo(number, delta)
  • .toBeGreaterThan(number)
  • .toBeLessThan(number)
  • .toBeCalled()
  • .toBeCalledWith(arg, um, ents)
  • .lastCalledWith(arg, um, ents)
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