public function it_returns_true_if_an_observer_is_removed()
{
$subject = new Subject();
$observer = $this->createMock('Rx\\ObserverInterface');
$subject->subscribe($observer);
$this->assertTrue($subject->hasObservers());
$this->assertTrue($subject->removeObserver($observer));
$this->assertFalse($subject->hasObservers());
}