Purport

verb: appear or claim to be or do something, especially falsely; profess.

Zero Dependency NodeJS require() Mocking For Unit Testing

---

Overrides standard requires() - just require & fire Purport before your other dependencies

const Purport = require("purport")()
const yourModule = require("yourModule")
const localImport = require("./example")

//Access your module like normal
yourModule.yourFunc()

//Your module is referenced via Purport as the string passed into require()
Purport.yourModule.stub("yourFunc", console.log)
Purport['./example'].record(console.log)

---

Methods

• stub(methodName, cb)
• record(methodName)
• mock(methodName, cb, events)
• reset()

---

stub(methodName, cb)

For when you just want to replace an existing function

methodName: String value with the exact name of your function (ex: function test()=>{} would be 'test')

cb: The actual method to execute; can use async/await or promises (ex: () => { return true })

Call to override your required libraries method with a stub function

Purport.yourModule.stub('testFunction', () => true) //replaces yourModule.testFunction
console.log(yourModule.testFunction()) //true

//also works with async/promises
Purport.yourModule.stub('testAsync', async () => { ... })
Purport.yourModule.stub('testPromise', new Promise( ... ))

---

record(methodName)

Observe the argument(s)/returned value(s) of existing functions

methodName: String value with the exact name of your function (ex: function test()=>{} would be 'test')

Exposes properties:

-Purport.yourModule.args.yourFunc - An array of argument arrays in the same order as the function was called

-Purport.yourModule.values.yourFunc - An array of the values returned by the function

-Purport.yourModule.callCount.yourFunc - number of times the method was called

-Purport.yourModule.wasCalled.yourFunc() - true if the method has been called at least once

Purport.yourModule.record('someFunc')
Purport.yourModule.callCount.someFunc // 0
Purport.yourModule.wasCalled.someFunc() // false

yourModule.someFunc()

Purport.yourModule.callCount.someFunc // 1
Purport.yourModule.wasCalled.someFunc() // true

TODO: async/promises? not tested/described ;(

---

mock(methodName, cb, hooks)

For when simpler method stubs just won't do. Extends stub & record with additional event hooks

methodName: String value with the exact name of your function (ex: function test()=>{} would be 'test')

cb: The actual method to execute; can use async/await, promises, or the original method (ex: () => { return true })

hooks: Optional events to fire directly before and after the function executes formatted like this: { preHook: ()=>{}, postHook: ()=>{} }

Exposes properties:

-Purport.yourModule.args.yourFunc - An array of argument arrays in the same order as the function was called

-Purport.yourModule.values.yourFunc - An array of the values returned by the function

-Purport.yourModule.callCount.yourFunc - number of times the method was called

-Purport.yourModule.wasCalled.yourFunc() - true if the method has been called at least once

const myTestFunc = () => { console.log("hello") }
const myOtherTestFunc = () => { console.log("goodbye") }

Purport.yourModule.mock('thatFunction', (arg1) => { console.log("how are you?") }, { preHook: myTestFunc, postHook: myOtherTestFunc })
Purport.yourModule.callCount.thatFunction // 0
Purport.yourModule.wasCalled.thatFunction() // false

yourModule.thatFunction() // hello, how are you?, goodbye

Purport.yourModule.callCount.thatFunction // 1
Purport.yourModule.wasCalled.thatFunction() // true

---

reset()

Call to reset your module to default

yourModule.falseFunction() //returns false
Purport.yourModule.stub('falseFunction', () => true)
yourModule.falseFunction() //returns true

Purport.yourModule.reset()
yourModule.falseFunction() //returns false