[8.x] Add expects to built-in Facade testing methods

[jasonmccreary]

The built-in testing layer for Facades wraps many underlying Mockery methods which is very great. But it's missing one of the most important testing methods - expects.

Currently shouldReceive is the only out of the box expectation. However, in most cases, shouldReceive does not provide the desired confidence. This can be confusing when new to testing.

In the end, just because something should receive a call, doesn't mean it did. So shouldReceive must included a count modifier such as once, twice, etc to trigger the desired behavior.

Given that it's often the case where you want to ensure something was called, I believe adding expects can help improve the testing experience within Laravel.

Within Mockery expects is simply an alias for shouldRecieve()->once(), yet it's a far more expressive method (which aligns nicely with Laravel), streamlines the code, and avoids the footgun scenario described above.

Before:

Cache::shouldReceive('remember')
        ->with('testing', 'is', 'important')
        ->once();

After:

Cache::expects('remember')
        ->with('testing', 'is', 'important');

[paras-malhotra]

@jasonmccreary isn't this a breaking change? If the underlying facade accessor class has an expects method, __callStatic would never be called and passed to the accessor class?

[jasonmccreary]

@paras-malhotra, possibly. I'd have to try it out. I assume that's the case for all of these testing methods though...

[paras-malhotra]

Yeah it's the same for all testing methods. I'm just saying this should go to master instead of 8x imo
/cc @taylorotwell