Cheatsheet - Jasmine

Cheetsheet — Jasmine

We reuse many things during any application development. While working with Jasmine, generally we use two sources, Jasmine Docs and Google. Even though we refer these resources, it consumes lot of time to get what we want i.e. right syntax with example.

To avoid doing this every time I have enlisted few of them as cheatsheet which can be used whenever required.

1. Create spy object with spy methods

mySpy = jasmine.createSpyObj('Contact', ['get','set']); 

2. Call fake method instead of real one.

mySpy.pickContact.and.callFake(function () {
  return {
    id: 10
  };
}); 

3. Call a spy method and return a value

var contact = {
  id: 10
};
mySpy.pickContact.and.returnValue(contact);

4. Call a spy method and return a async value

var contact = {
  id: 10
};
mySpy.pickContact.and.returnValue(asyncData(contact)); 

5. Install a spy on existing object

spyOn(Contact, 'get'); // Spy on 'get' method of Contact

6. Install a spy on a property

spyOnProperty(Contact, 'name'); // Spy on 'name' property of Contact

7. Check spy method called or not

expect(Contact.get).toHaveBeenCalled();      // Check if called
expect(Contact.set).not.toHaveBeenCalled();  // Check if not called

8. Check spy method is called with particular parameters

expect(Contact.get).toHaveBeenCalledWith('Ganesh', 'Gaitonde');

9. Check call counts

expect(mySpy.get.calls.count()).toBe(1, ‘one call’);

10. Check most recent call

expect(mySpy.get.calls.mostRecent().args[1]).toEqual('getErr');

11. Reset Spy calls

var myService = jasmine.createSpyObj('MyService', ['getId']);
myService.getId.calls.reset();

12. Override global spy in local file and reset it after all tests are executed.

...
const areArraysEqual = UvUtilService.areArraysEqual();
...
it('applyFilters should apply Filters', () => {
  ...
  expect(HomeService.filterCards).not.toHaveBeenCalled();
  UvUtilService.areArraysEqual.and.callFake(() => {
    return false;
  });
  expect(HomeService.filterCards).toHaveBeenCalled();
  ...
});
afterAll(() => {
  UvUtilService.areArraysEqual.and.callFake(() => {
    return areArraysEqual;
  });
});

13. fakeAsync() with tick()→ No actual call from spec file

14. async() with fixture.whenStable()→ Actual call from spec file