https://jasmine.github.io/pages/docs_home.html https://howtodoinjava.com/scripting/javascript/jasmine-unit-testing-tutorial/

jasmine

//This is test suite
describe("Test Suite", function() {
    it("test spec", function() {
        expect( expression ).toEqual(true);
    });
});
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Matchers

toBe()	passed if the actual value is of the same type and value as that of the expected value. It compares with === operator
toEqual()	works for simple literals and variables;
should work for objects too
toMatch()	to check whether a value matches a string or a regular expression
toBeDefined()	to ensure that a property or a value is defined
toBeUndefined()	to ensure that a property or a value is undefined
toBeNull()	to ensure that a property or a value is null.
toBeTruthy()	to ensure that a property or a value is true
ToBeFalsy()	to ensure that a property or a value is falseToBe
toContain()	to check whether a string or array contains a substring or an item.
toBeLessThan()	for mathematical comparisons of less than
toBeGreaterThan()	for mathematical comparisons of greater than
toBeCloseTo()	for precision math comparison
toThrow()	for testing if a function throws an exception
toThrowError()	for testing a specific thrown exception
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Spy

var calc;

beforeEach(function() {
    calc = new MathUtils();
    spyOn(calc, 'sum');
});

it("should be able to calculate sum of 3 and 5", function() {
  //call any method
  calc.sum(3,5);
  
  //verify it got executed
  expect(calc.sum).toHaveBeenCalled();
  expect(calc.sum).toHaveBeenCalledWith(3,5);
});

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tape = jasmine.createSpyObj('tape', ['play', 'pause', 'stop', 'rewind']);
tape.play();
 
//Use it for testing
 expect(tape.play.calls.any()).toEqual(true);
 
.calls.any()	returns false if the spy has not been called at all, and then true once at least one call happens.
.calls.count()	returns the number of times the spy was called
.calls.argsFor(index)	returns the arguments passed to call number index
.calls.allArgs()	returns the arguments to all calls
.calls.all()	returns the context (the this) and arguments passed all calls
.calls.mostRecent()	returns the context (the this) and arguments for the most recent call
.calls.first()	returns the context (the this) and arguments for the first call
.calls.reset()	clears all tracking for a spy
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test-boilerplate

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { BannerComponent } from './banner.component';

describe('BannerComponent (minimal)', () => {
  let component: BannerComponent;
  let fixture: ComponentFixture<BannerComponent>;

  beforeEach(() => {
    TestBed.configureTestingModule({
      declarations: [ BannerComponent ]
    });
    fixture = TestBed.createComponent(BannerComponent);
    component = fixture.componentInstance;
  });
  
  it('should create', () => {
    expect(component).toBeDefined();
  });
  
  it('should contain "banner works!"', () => {
    const bannerElement: HTMLElement = fixture.nativeElement;
    const p = bannerElement.querySelector('p');
    expect(bannerElement.textContent).toContain('banner works!');
    expect(p.textContent).toEqual('banner P works!');
  });
  
});