Harness the power of Jasmine's createSpy() and createSpyObj() functions to mock & spy all at once!

some.component.spec.ts

import { SomeComponent } from './some.component.js';

describe('SomeComponent:', () => {
  let component: SomeComponent;
  let mockDepOne: any;
  let mockDepTwo: any;

  beforeEach(() => {
    mockDepOne = {
      doSomething: jasmine.createSpy('doSomething').and.returnValue('0123456789')
    };
    mockDepTwo = jasmine.createSpyObj('DepTwo', ['doSomethingElse']);
    component = new SomeComponent(mockDepOne, mockDepTwo);
  });

  describe('someMethod', () => {

    describe('called with true', () => {

      // notice we do not require a spyOn() method
      it('should call depOne.doSomething', () => {
        component.someMethod(true);
        expect(mockDepOne.doSomething).toHaveBeenCalled();
      });

    });

    describe('called with false', () => {

      // notice we do not require a spyOn() method
      it('should call depOne.doSomething', () => {
        component.someMethod(false);
        expect(mockDepTwo.doSomethingElse).toHaveBeenCalled();
      });

    });

  });

});

some.component.ts

import { DepOne, DepTwo } from './dependencies';

export class SomeComponent {

  constructor(
    private depOne: DepOne,
    private depTwo: DepTwo
  ) { }

  someMethod(someCondition: boolean): void {
    if (someCondition) {
      this.depOne.doSomething();
    } else {
      this.depTwo.doSomethingElse();
    }
  }

}