proposal: net/http/httptest: add support for http.ResponseController to ResponseRecorder #60229
Description
Proposal #54136 (implemented in CL 436890 which is part of Go 1.20) added the "http".ResponseController type, which allows manipulating per-request timeouts. This is especially useful for programs managing long-running HTTP connections such as Mercure.
However, testing HTTP handlers leveraging per-request timeouts is currently cumbersome (even if doable) because "net/http/httptest".ResponseRecorder isn't compatible yet with "http".ResponseController.
To make it fully compatible with response controllers and improve the testing experience, I propose the following additions to its public API:
type ResponseRecorder struct {
// ...
// ReadDeadline is the last read deadline that has been set using
// "net/http".ResponseController
ReadDeadline time.Time
// WriteDeadline is the last write deadline that has been set using
// "net/http".ResponseController
WriteDeadline time.Time
}
// SetReadDeadline allows using "net/http".ResponseController.SetReadDeadline()
// with the recorder.
//
// The deadline is recorded but is not enforced.
// To prevent flaky tests reads made after the deadline will work
// as if no deadline was set.
//
// To retrieve the deadline, use rw.ReadDeadline.
func (rw *ResponseRecorder) SetReadDeadline(deadline time.Time) error
// SetWriteDeadline allows using "net/http".ResponseController.SetWriteDeadline()
// with the recorder.
//
// The deadline is recorded but is not enforced.
// To prevent flaky tests writes made after the deadline will work
// as if no deadline was set.
//
// To retrieve the deadline, use rw.WriteDeadline.
func (rw *ResponseRecorder) SetWriteDeadline(deadline time.Time) errorAll new methods are part of the contract that response types must honor to be usable with "HTTP".ResponseController.
As discussed below, deadlines are recorded but not enforced to prevent flaky tests.
Proposal implementation: #60231