public function testGetValue()
 {
     $method = new ReflectionMethod('PaynetEasy\\PaynetEasyApi\\Transport\\Response', 'getValue');
     $method->setAccessible(true);
     $this->object->exchangeArray(array('first-key' => 1, 'first_key' => 2));
     $this->assertEquals(2, $method->invoke($this->object, 'first_key'));
     $this->assertNull($method->invoke($this->object, 'first'));
 }