Testing can be frustrating to learn, but it is worth it. It can be difficult to see why it is worth it, but some key points: encourages better architecture ("bad" code is hard to test), protects against regressions, is a form of documentation, makes it easier to onboard other developers into the codebase, and in the end it will actually speed up development especially as a codebase grows as you are able to make changes with confidence and immediately see when things break. For your specific case, if you are creating a unit test for an addNotes() method then generally speaking you probably want to mock any dependencies you are dealing with - that will mean doing something like using jest.mock, or using useValue in your providers array in the TestBed set up, or supplying a mock component in the declarations, etc. If you are running into a lot of trouble mocking things, then it might also be a sign that the code might need to be refactored into simpler parts. More on reddit.com

I work on an angular application with 3000+ unit tests (93% code coverage for 40k lines), we use the angular testbed and we test against the HTML (although this wasn't always the case, it has been for the last 2000 tests or so). We've found them to be invaluable (which is why we spend time writing them) The trick for us was small components and proper separation of concerns. You mention needing to include modules "needed by other components" this suggests you are either intentionally writing integration tests (which we use protractor for) or you are incorrectly writing unit tests. If you are trying to write unit tests, everything that isn't the thing you are testing should be mocked in the unit test. If you are testing component A, you aren't concerned with what component B does (that is covered in component B's unit test) so you mock it. Proper mocking can help cut down on "I changed a thing in one component, now I need to update the tests in 40 places" (a mistake we've certainly made). To give you an idea, it takes me about an hour to unit test a medium sized component (~60 lines) to 100% coverage including HTML. Some of our older stuff, before we got pretty good at testing (200+ line components, poor separation of concerns) might take half a day. Some people mentioned cypress and other libraries, I've never tried them but I would argue this: separation of concerns, small components, and proper unit testing strategies are time savers regardless of the testing framework and whether or not you dump angular testbed you should strive to do these things in your code, you'll be glad you did. More on reddit.com

This has been an incredible guide for me. It also has a downloadable e-book version. https://testing-angular.com/ More on reddit.com

I like to stick to what the Angular framework comes with and that is TestBed, Jasmine and Karma. Like many have mentioned, it will give you the best support because if these don't work, then Angular will have to fix it. www.testing-angular.com is a great resource to learn all about testing angular and it uses Jasmine and Karma. More on reddit.com