Angular Unit and Integration Testing Best Practices

[Greg Finzer]

I am an architect normally working in the Microsoft .NET space that is brand new to the Angular world.  I am looking for advice on the best practices for testing an Angular application.  Normally here is the stack that I would use for testing an ASP.NET MVC application:

Unit Tests - NUnit with MOQ, language C#

Integration Tests - NUnit, language C#

End to End Tests (User Interface Tests) - NUnit, Selenium, language C#

The client has zero automated tests currently on their legacy system which is a combination of Classic ASP with COM objects, ASP.NET Webforms, and ASP.NET MVC.  They are looking to replace their front end with Angular 4 and keep their WCF back end.  They have a complex database driven custom rules engine that will also stay.  Normally I would write unit tests against class methods in C#, mocking any external services.  Typical of organizations that have no automated tests, their code is tightly integrated with their external systems, and would require a lot of refactoring just to be able to test it.

My initial thoughts are to create some service integration tests for Angular in Karma/Jasmine and some Selenium/Protractor tests for the End to End Tests.  What should be tested in Angular as far as Unit Tests?  How would you do TDD in Angular?