Mock repositories

[yoannLafore]

Hello,
This pull request aims to provide the boiler plate code needed to mock the methods of the repositories.
This code is contained in the classes MockPostRepositoryService and MockUserRepositoryService.

Here is an example of how such a class can be used in a test to mock a repository method

late MockPostRepositoryService postRepository;

setUp(() {
  // Initialize the mock
  postRepository = MockPostRepositoryService();
});

test("some test", () {
  final point = ...
  final kmPostRadius = ...

  // To mock the [getNearPosts] method when it is called with particular parameters
   when(postRepository.getNearPosts(point, kmPostRadius)).thenAnswer(
        // Here, it is mocked to return an empty list
        (_) async => [], 
   );

  // From this point on, when the "postRepository.getNearPosts(point, kmPostRadius)" is called, the mock overrides
  // enters into action and an empty list will be returned
});

This PR also provides a class to easily generate mock data for UserFirestore which can be useful when testing.
This class is MockUserFirestore located under test/models/database/user.

Finally, MockFirestorePost has been renamed to MockPostFirestore as well as being moved to test/models/database/user for consistency.

Important note:

For the mock of the repositories, the way the code is written can misleadingly make believe that a particular value will be returned whithout having to mock it in the tests with when(...) ....
This, is not the case, if a method from the mock repository is called without having properly set up the when(...) ... before, an exception will be thrown.

For example, in the MockUserRepositoryService, we have the following override:

  @override
  Future<bool> doesUserExist(UserIdFirestore uid) {
    return super.noSuchMethod(
      Invocation.method(#doesUserExist, [uid]),
      returnValue: Future.value(false),
    );
  }

In our test code we could be tempted to simply call:

userRepository.doesUserExist(...);

expecting it to return it false.

This wont work and will throw an exception.
The correct way is:

when(userRepository.doesUserExist(...)).thenAnswer(
  () async {return false;}
);

userRepository.doesUserExist(...);

[gruvw]

I think most of those newly created methods should be static. You should not need an instance of MockPostFirestore or similar.

[gruvw]

Also, it is a good idea to mimic the directory structure of the original lib in the tests 👍

[yoannLafore]

Thanks for your feedback @gruvw, you're right, the methods of MockPostFirestore and MockUserFirestore can be static.
This is corrected in commits 14fec27 and 0887b80 👍

[Aderfish]

good job, looks good to me