callMethod(v, "Register", c.name, c.h)
			}

			if e, ok := v.(error); !ok || e != nil {
				err = e
			}
		}

		if len(data.err) > 0 && err == nil {
			t.Errorf("callbacks tests #%v should got error %v, but not", idx+1, data.err)
		} else if len(data.err) == 0 && err != nil {
			t.Errorf("callbacks tests #%v should not got error, but got %v", idx+1, err)
		}