WC_Order::key_is_valid PHP Method

    public function key_is_valid($key)
    {
        return $key === $this->get_order_key();
    }

 /**
  * Test: key_is_valid
  */
 function test_key_is_valid()
 {
     $object = new WC_Order();
     $object->save();
     $this->assertFalse($object->key_is_valid('1234'));
     $object->set_order_key('1234');
     $this->assertTrue($object->key_is_valid('1234'));
 }