How to prevent PhpStorm from showing an Expected... warning when using PHPUnit mocks?

I found a workaround to this problem in the Jetbrain blog at PhpStorm Type Inference and Mocking Frameworks. The important part:

By default, PhpStorm is capable of figuring out the available methods on the mock object. However, it only displays those for PHPUnit’s PHPUnit_Framework_MockObject_MockObject class. Fortunately, we can solve this by instructing PhpStorm to infer type information from other classes as well, by using a simple docblock comment.

So to make the warning disappear, we need to add /** @var InterfaceA */ /** @var InterfaceA|PHPUnit_Framework_MockObject_MockObject */ (cudos to Supericy) to let PhpStorm know our mock actually implements InterfaceA:

interface InterfaceA{                                

}                                                    

class ClassA{                                        
    public function foo(InterfaceA $foo){}           
}                                                    

class PhpStormTest extends PHPUnit_Framework_TestCase
{                                                    
    public function testFoo(){   
        /** @var InterfaceA|PHPUnit_Framework_MockObject_MockObject */            
        $mock = $this->getMock("InterfaceA");        
        $a = new ClassA();                           
        $a->foo($mock);                              
    }                                                
} 

This bugged me for some time, hope it helps someone :)

Edit

Since PHPUnit_Framework_MockObject_MockObject is really ugly to type, you can abbreviate it via MOOMOO and let PHPStorms auto-complete do the rest: