[Chore] Set up a code generator or a mocking library for generating stub, fake, mock types for unit testings

[Thieurom]

Why

In order to unit test a type that depends on other types, we inject those dependencies with the mocked implementations.
Currently, in the project, we manually write them by hand. We need to set up a code generator or a mocking library for generating those mocked implementations so that:

• We have the necessary mocked types with clear and consistent API (exposed properties and methods) available.
• Developers just need to focus on writing unit tests.

We can choose between:

• A general-purpose code generator likes Sourcery
• A library specific for mocking likes Mockingbird, Cuckoo or others

Who Benefits?

Developers who implement features that require accompanying unit tests.