Jasmine: typesafe stubs for container component tests

problem:

container component tests are slow and painful. require mocking a lot of objects sometimes multiple levels deep.

option 1: shallow tests with no errors schema

https://angular.io/guide/testing#shallow-component-tests-with-no_errors_schema

Challenges:

• compiler no longer alerts you to mistakes such as misspelled or misused components and directives (from angular docs)
• can't validate inputs are set

the good:

• lighter tests, faster

option 2: test doubles

Challenges:

• duplicating components for stubs can create a lot of maintenance and fall apart over time
• TestBed.get will not work

the good:

• lighter tests, fast

option 3: load all children and write integration tests

Challenges:

• heavy, hard to write tests for higher order components
• slow to run
• can't write isolated unit tests

the good:

• if your after full integration tests this can be useful (in moderation)

solution: typesafe stubs

Challenges:

• duplicating components for stubs can create a lot of maintenance if not tied together with implementation
• TestBed.get will not work

the good:

• lighter tests, fast