typescript-mockify

Typescript mocking library. Makes it easy to create mocks in typescript. Spies are automatically added on every mock function. Properties that are not mapped in the constructor will get default values.

Installing

$ npm install typescript-mockify --save

Usage

import typescript-mockify

import {ConstructorArguments, Mock, MockBuilder} from "typescript-mockify";

If you would have the following class:

interface ICar {
    speed: number;
    brand: string;
    age: number;
 
    drive(speed: number): void;
    stop(): void;
    toString(): string;
}
 
class Car implements ICar {
    public speed: number = 0;
 
    constructor(public brand: string, public age: number) {
    }
 
    public drive(speed: number): void {
        this.speed = speed;
    }
 
    public stop(): void {
        this.speed = 0;
    }
 
    public toString(): string {
        return "brand:" + this.brand + ", speed:" + this.speed + ", age:" + this.age;
    }
}

You can create a mock like this..

var mockedCar: Mock<ICar> =
    new MockBuilder<ICar>().createInstance(Car, new ConstructorArguments()
        .map("brand", "vw")
        .map("age", 12));

The actual instance will be in the instance property

var actualInstance = mockedCar.instance;

Even though typescript-mockify has created spies for every function, you can still declare returnvalues in an easy way

mockedCar
    .setupMethod("toString").andReturn("my mocked returnvalue")
    .setupMethod("dummyFunc").andCallFake(() => _.noop);

Or directly fetch the spy of a stubbed function...

var driveSpy: Spy = mockedCar
    .setupMethod("drive").getSpy();

You can also use the callback notation to keep the chain alive

mockedCar
    .setupSpy("drive", (driveSpy: Spy) => driveSpy.and.callFake(_.noop))
    .setupSpy("toString", (toStringSpy: Spy) => toStringSpy.and.returnValue("I came from the spy"));

Or just use it directly...

var driveSpy: Spy = mockedCar.instance.drive;

Example

Just a tiny example to show the difference between the real instance and the mock instance

var car: ICar = new Car("vw", 10);
console.log(car.speed); // 0
car.drive(100);
console.log(car.speed); // 100
car.stop();
console.log(car.speed); // 0
console.log(car.toString()); // brand:vw, speed:0, age:10
 
var mockedCar: Mock<ICar> = new MockBuilder<ICar>()
    .withCallConstructor(true)
    .createInstance(Car, new ConstructorArguments()
        .map("brand", "vw")
        .map("age", 12))
    .setupMethod("toString").andReturn("mockedstr");
 
console.log(mockedCar.instance.speed); // 0
car.drive(100);
console.log(mockedCar.instance.speed); // 0
car.stop();
console.log(mockedCar.instance.speed); // 0
console.log(mockedCar.instance.toString()); // mocked str