PHPUnit, mocked interfaces, and instanceof

Question

Sometimes in my code, I'll check to see if a particular object implements an interface:

if ($instance instanceof Interface) {};

However, creating mocks of said interface in PHPUnit, I can't seem to pass that test.

 // class name is Mock_Interface_431469d7, does not pass above check
 $instance = $this->getMock('Interface'); 

I understand that having a class named Interface is different from a class implementing Interface, but I'm not sure how to get deal with this.

Am I forced to mock a concrete class that implements Interface? Wouldn't that defeat the purpose of using an interface for portability?

Thanks

Answer 1

This works for me:

$mock = $this->getMock('TestInterface');
$this->assertTrue($mock instanceof TestInterface);

Maybe it's a typo or maybe $instance isn't what you think it is?