ng2-pipes/src/app/pipes/array/initial.spec.ts

Useful angular2 pipes

import {InitialPipe} from './initial';

describe('InitialPipe', () => {
  let pipe: InitialPipe;

  beforeEach(() => {
    pipe = new InitialPipe();
  });

  it('should check that nothing happens if there are no parameters', () => {
    let arr = [1, 2, 3];
    let result = pipe.transform(arr);
    expect(result).toEqual([1, 2, 3]);
  });

  it('should slice properly', () => {
    expect(pipe.transform([1, 2, 3, 4], 1)).toEqual([1, 2, 3]);
    expect(pipe.transform([1, 2, 3, 4], 3)).toEqual([1]);
  });

  it('should slice properly array of objects', () => {
    let fooObj = {id: 1, name: 'foo'},
        barObj = {id: 2, name: 'bar'},
        cazObj = {id: 3, name: 'caz'};

    expect(pipe.transform([fooObj, barObj, cazObj], 1)).toEqual([fooObj, barObj]);
  });
});