jasmine-auto-spies

jasmine-auto-spies

Create automatic spies from classes in jasmine tests. If you're using TypeScript it'll also create auto spies for Promise or Observable returning methods and provide type completion.

What is it good for?

• Keep you tests DRY - no more repeated spy setup code, no need for separate spy files

• Type completion for both the original Class and the spy methods

• Automatic return type detection by using a simple decorator

Installation

npm install -D jasmine-auto-spies

Setup

In your tsconfig.json set these 2 flags -

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
  }
}

Usage

1. Spying on regular sync methods

Let's say you have a class -

class MyService{
  getName(): string{
    return 'Bonnie';
  }
}

This is how you create an automatic spy for it -

import { Spy, createSpyFromClass } from 'jasmine-auto-spies';

let myServiceSpy: Spy<MyService>;

beforeEach( ()=> {
  myServiceSpy = createSpyFromClass( MyService );
});

it( ()=> {
  myServiceSpy.getName.and.returnValue('Fake Name');
  
  ... (the rest of the test) ...
});

2. Spy on a Promise returning method

First, annotate the method with @AsyncSpyable -

import { AsyncSpyable } from 'jasmine-auto-spies';

export class MyService{

   @AsyncSpyable() // <-- MUST ADD THIS
   getItems(): Promise<any> {
      return Promise.resolve( itemsList );
   } 
}

Now you can use the resolveWith or rejectWith methods -

import { Spy, createSpyFromClass } from 'jasmine-auto-spies';

let myServiceSpy: Spy<MyService>;

beforeEach( ()=> {
  myServiceSpy = createSpyFromClass( MyService )
});

it( ()=>{
  myServiceSpy.getItems.and.resolveWith( fakeItemsList );
  // OR
  myServiceSpy.getItems.and.rejectWith( fakeError );
});

3. Spy on a Observable returning method

First, annotate your Observable returning method with @AsyncSpyable -

import { AsyncSpyable } from 'jasmine-auto-spies';

export class MyService{

   @AsyncSpyable() // <-- MUST ADD THIS
   getProducts(): Observable<any> {
    return Observable.of( productsList );
   }
}

Now you can use the nextWith or nextWithError methods -

import { Spy, createSpyFromClass } from 'jasmine-auto-spies';

let myServiceSpy: Spy<MyService>;

beforeEach( ()=> {
  myServiceSpy = createSpyFromClass( MyService )
});

it( ()=>{
  myServiceSpy.getProducts.and.nextWith( fakeProductsList);
  myServiceSpy.getProducts.and.nextWithError( fakeError );
});

Manual Setup

If you need to manually configure async methods by names you could pass them as arrays of strings -

let spy = createSpyFromClass(
            MyClass, 
            ['promiseMethod1', 'promiseMethod2'],
            ['observableMethod1', 'observableMethod2']
          );