// Test that we use the older backward compatible cancellation protocol
// when a RoundTripper is registered via RegisterProtocol.
func TestAltProtoCancellation(t *testing.T) {
	defer afterTest(t)
	tr := &Transport{}
	c := &Client{
		Transport: tr,
		Timeout:   time.Millisecond,
	}
	tr.RegisterProtocol("cancel", cancelProto{})
	_, err := c.Get("cancel://bar.com/path")
	if err == nil {