Context

WithContext sets the request context. The handler receives it from r.Context(), so deadlines, cancellation and context values all reach it:

ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
ctx = context.WithValue(ctx, ctxKey("tenant"), "acme")

apitest.Handler(handler).
	Get("/hello").
	WithContext(ctx).
	Expect(t).
	Status(http.StatusOK).
	End()

Common uses are:

• Checking that a handler stops work when the client goes away, by cancelling the context.
• Checking that a handler respects a deadline.
• Injecting values that middleware would normally add, such as an authenticated user, when testing a handler without its middleware.

To check what a client sees when a handler is too slow, see handler timeouts.