observer-spy VS ng-mocks

Observer-Spy is from Shai Reznik and is indispensable when testing observables. It takes so much of the boilerplate and scariness out of testing. auto-spies is another library from Shai. This library will create spies for you from your objects. ng-mocks has become a must-have in my testing toolkit. It allows some amazing things to happen. For example, imports: [MockModule(MyModuleDependency)]. It makes testing so easy and often painless.

Is the Angular team aware of NG Mocks and NG Spectator?

No neither of those. You're unit testing the component, so you don't want any external interference. You can create a mock version of the service, I like using ng-mocks to simplify a lot of this: https://www.npmjs.com/package/ng-mocks

No way, you just mock the services. Check out this library: https://www.npmjs.com/package/ng-mocks

I recommend using MockModule from ng-mocks https://www.npmjs.com/package/ng-mocks

8. NG-Mocks

You can have a look at ng-mocks. It provides a great toolset for angular mocks.

Also, for mocking, I recommend looking into ng-mocks. https://github.com/ike18t/ng-mocks It makes mocking really easy.

Correct. When unit testing, you want to test the unit (parent component) in isolation. To do this, you can use something like ng-mocks (my personal favorite) to create mock components. You could also use the NO_ERRORS_SCHEMA but I don't recommend this because I like to verify that my component loads w/ all of its dependencies (even if the are just mocks). If you test your parent component w/ all of its child components, then you are doing a form of integration testing. I tend to refer to it as a grey area between unit and integration testing because there are valuable tests that can be written fairly easily and cheaply that don't truly isolate parent components from their child components.