References
- https://www.npmjs.com/package/expect
- https://github.com/mjackson/expect
- Expect.Js Cheat Sheet - Cheat Sheet Maker
Assertions on spies
expect(spy.calls.length).toEqual(1)
expect(spy.calls[0].context).toBe(video)
expect(spy.calls[0].arguments).toEqual([ 'some', 'args' ])
expect(spy.getLastCall().arguments).toEqual(...)
expect(spy).toHaveBeenCalled()
expect(spy).toHaveBeenCalledWith('some', 'args')
Spies
const video = {
play: function () { ··· }
}
spy = expect.spyOn(video, 'play')
spy = expect.spyOn(···)
.andCallThrough() // pass through
.andCall(fn)
.andThrow(exception)
.andReturn(value)
Chaining assertions
expect(3.14)
.toExist()
.toBeLessThan(4)
.toBeGreaterThan(3)
Assertions can be chained.
Assertions
expect(x).toBe(y)
.toBe(val)
.toEqual(val)
.toThrow(err)
.toExist() // aka: toBeTruthy()
.toNotExist() // aka: toBeFalsy()
.toBeA(constructor)
.toBeA('string')
.toMatch(/expr/)
.toBeLessThan(n)
.toBeGreaterThan(n)
.toBeLessThanOrEqualTo(n)
.toBeGreaterThanOrEqualTo(n)
.toInclude(val) // aka: toContain(val)
.toExclude(val)
.toIncludeKey(key)
.toExcludeKey(key)
Also: toNotBe
, toNotEqual
, etc for negatives.
Using
npm install --save-dev expect
{: .-setup}
// using ES6 modules
import expect, { createSpy, spyOn, isSpy } from 'expect'
// using CommonJS modules
var expect = require('expect')
var createSpy = expect.createSpy
var spyOn = expect.spyOn
var isSpy = expect.isSpy
Expect is a library for assertions in tests.
See: mjackson/expect
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