Update return type for mockPost()

[wvega-godaddy]

Summary

The return type must be a WP_Post and a mockery mock at the same time. I believe that the method needs to use an intersection type instead of an union one.

Details

Unfortunately, WP_Post cannot be used in an intersection type, because the class is declared as final (related discussions in PHPStan's repo). The current version of mockPost() was always returning Mockery\LegacyMockInterface so I think it still makes sense to update the return type.

I also updated the return type of mockWp() to return an intersection of WP and Mockery mock interfaces. Since WP is not final, we can use the intersection type directly.

Contributor checklist

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly
• I have added tests to cover changes introduced by this pull request
• All new and existing tests pass

Reviewer checklist

• Code changes review
• Documentation changes review
• Unit tests pass
• Static analysis passes

[coveralls]

coverage: 65.646%. remained the same when pulling 5691885 on chore/update-returned-type-for-mock-post into db23b60 on trunk.