/**
  * @test
  */
 public function Can_check_if_instances_are_registered()
 {
     // arrange
     $Container = new TestContainer();
     $type = 'NonInjectableClass';
     // act
     $first = $Container->isRegistered($type);
     $Container->registerInstance($type, NonInjectableClass::newNonInjectableClass());
     $second = $Container->isRegistered($type);
     // assert
     $this->assertFalse($first);
     $this->assertTrue($second);
 }