public function testWhenSwitchOffAndOnReturnsCorrectValue()
 {
     $value = 'non date value';
     $mockFunction = new PHPUnit_Extensions_MockFunction('date', $this);
     $mockFunction->expects($this->any())->will($this->returnValue($value));
     $mockFunction->disable();
     $mockFunction->enable();
     $this->assertEquals($value, date());
 }