net/http: add tests for Server.ReadTimeout and server.WriteTimeout

We don't seem to have tests verifying that handler reads from the
request body or writes to the response body time out properly.
Add some.

For #49837
For #56478

Change-Id: I0828edd6c86b071073fd1b22ccbb24f86114ab94
Reviewed-on: https://go-review.googlesource.com/c/go/+/446255
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

Author: neild

src/net/http/serve_test.go

@@ -736,6 +736,75 @@ func testServerTimeoutsWithTimeout(t *testing.T, timeout time.Duration, mode tes
 	return nil
 }
 
+func TestServerReadTimeout(t *testing.T) { run(t, testServerReadTimeout) }
+func testServerReadTimeout(t *testing.T, mode testMode) {
+	if mode == http2Mode {
+		t.Skip("https://go.dev/issue/49837")
+	}
+	respBody := "response body"
+	cst := newClientServerTest(t, mode, HandlerFunc(func(res ResponseWriter, req *Request) {
+		_, err := io.Copy(io.Discard, req.Body)
+		if !errors.Is(err, os.ErrDeadlineExceeded) {
+			t.Errorf("server timed out reading request body: got err %v; want os.ErrDeadlineExceeded", err)
+		}
+		res.Write([]byte(respBody))
+	}), func(ts *httptest.Server) {
+		ts.Config.ReadTimeout = 5 * time.Millisecond
+	})
+	pr, pw := io.Pipe()
+	res, err := cst.c.Post(cst.ts.URL, "text/apocryphal", pr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer res.Body.Close()
+	got, err := io.ReadAll(res.Body)
+	if string(got) != respBody || err != nil {
+		t.Errorf("client read response body: %q, %v; want %q, nil", string(got), err, respBody)
+	}
+	pw.Close()
+}
+
+func TestServerWriteTimeout(t *testing.T) { run(t, testServerWriteTimeout) }
+func testServerWriteTimeout(t *testing.T, mode testMode) {
+	if mode == http2Mode {
+		t.Skip("https://go.dev/issue/56478")
+	}
+	for timeout := 5 * time.Millisecond; ; timeout *= 2 {
+		errc := make(chan error, 2)
+		cst := newClientServerTest(t, mode, HandlerFunc(func(res ResponseWriter, req *Request) {
+			errc <- nil
+			_, err := io.Copy(res, neverEnding('a'))
+			errc <- err
+		}), func(ts *httptest.Server) {
+			ts.Config.WriteTimeout = timeout
+		})
+		res, err := cst.c.Get(cst.ts.URL)
+		if err != nil {
+			// Probably caused by the write timeout expiring before the handler runs.
+			t.Logf("Get error, retrying: %v", err)
+			cst.close()
+			continue
+		}
+		defer res.Body.Close()
+		_, err = io.Copy(io.Discard, res.Body)
+		if err == nil {
+			t.Errorf("client reading from truncated request body: got nil error, want non-nil")
+		}
+		cst.close()
+		select {
+		case <-errc:
+			err = <-errc // io.Copy error
+			if !errors.Is(err, os.ErrDeadlineExceeded) {
+				t.Errorf("server timed out writing request body: got err %v; want os.ErrDeadlineExceeded", err)
+			}
+			return
+		default:
+			// The write timeout expired before the handler started.
+			t.Logf("handler didn't run, retrying")
+		}
+	}
+}
+
 // Test that the HTTP/2 server handles Server.WriteTimeout (Issue 18437)
 func TestWriteDeadlineExtendedOnNewRequest(t *testing.T) {
 	run(t, testWriteDeadlineExtendedOnNewRequest)