In an interesting post to his blog Ahmad Hajjar shows you how to use to Go! PHP AOP framework to help mock objects in your unit tests. The Go! AOP framework provides some of the base functionality for using aspect-oriented programming techniques in your code.

These have been always very important questions in software development industry; what should I test in unit testing? And how can I make tests as small as possible, and how to avoid testing already tested code? or 3rd party libraries? [...] In principle, unit test must fail for one and ONLY ONE reason, this makes sense actually, as it complies with the S in the SOLID object-oriented design principles. [...] We can use mocks in the problem listed above, to make the unit test, real unit test, that is testing only the things that needs to be tested. [...] However, what we are going to do today is something different. OK! Why should we re-invent the wheel? the answer is : because it is simpler wheel ! also it is a wheel that uses different technology which is AOP.

He uses a simple Laravel application and the Go! framework for his testing examples. He uses the AOP functionality from Go! as the mock handling instead of something like PHPUnit's own mocking or Mockery. He shows how to configure the AOP functionality first, then creates a basic aspect class with a few interceptors for method calls. He creates an AopMocker class that adds the class requested to the mock configuration. Finally he improves the initial unit test example using these tools, building mocks for User and Post classes and making the same assertion.