1 files changed, 52 insertions, 10 deletions

diff --git a/src/net/http/clientserver_test.go b/src/net/http/clientserver_test.go
index 19dc156003..0d231b87b0 100644
--- a/src/net/http/clientserver_test.go
+++ b/src/net/http/clientserver_test.go
@@ -64,21 +64,23 @@ func newClientServerTest(t *testing.T, h2 bool, h Handler, opts ...interface{})
 		tr: &Transport{},
 	}
 	cst.c = &Client{Transport: cst.tr}
+	cst.ts = httptest.NewUnstartedServer(h)
 
 	for _, opt := range opts {
 		switch opt := opt.(type) {
 		case func(*Transport):
 			opt(cst.tr)
+		case func(*httptest.Server):
+			opt(cst.ts)
 		default:
 			t.Fatalf("unhandled option type %T", opt)
 		}
 	}
 
 	if !h2 {
-		cst.ts = httptest.NewServer(h)
+		cst.ts.Start()
 		return cst
 	}
-	cst.ts = httptest.NewUnstartedServer(h)
 	ExportHttp2ConfigureServer(cst.ts.Config, nil)
 	cst.ts.TLS = cst.ts.Config.TLSConfig
 	cst.ts.StartTLS()
@@ -1143,19 +1145,30 @@ func testBogusStatusWorks(t *testing.T, h2 bool) {
 	}
 }
 
-func TestInterruptWithPanic_h1(t *testing.T) { testInterruptWithPanic(t, h1Mode) }
-func TestInterruptWithPanic_h2(t *testing.T) { testInterruptWithPanic(t, h2Mode) }
-func testInterruptWithPanic(t *testing.T, h2 bool) {
-	log.SetOutput(ioutil.Discard) // is noisy otherwise
-	defer log.SetOutput(os.Stderr)
-
+func TestInterruptWithPanic_h1(t *testing.T)     { testInterruptWithPanic(t, h1Mode, "boom") }
+func TestInterruptWithPanic_h2(t *testing.T)     { testInterruptWithPanic(t, h2Mode, "boom") }
+func TestInterruptWithPanic_nil_h1(t *testing.T) { testInterruptWithPanic(t, h1Mode, nil) }
+func TestInterruptWithPanic_nil_h2(t *testing.T) { testInterruptWithPanic(t, h2Mode, nil) }
+func TestInterruptWithPanic_ErrAbortHandler_h1(t *testing.T) {
+	testInterruptWithPanic(t, h1Mode, ErrAbortHandler)
+}
+func TestInterruptWithPanic_ErrAbortHandler_h2(t *testing.T) {
+	testInterruptWithPanic(t, h2Mode, ErrAbortHandler)
+}
+func testInterruptWithPanic(t *testing.T, h2 bool, panicValue interface{}) {
+	setParallel(t)
 	const msg = "hello"
 	defer afterTest(t)
+
+	var errorLog lockedBytesBuffer
+
 	cst := newClientServerTest(t, h2, HandlerFunc(func(w ResponseWriter, r *Request) {
 		io.WriteString(w, msg)
 		w.(Flusher).Flush()
-		panic("no more")
-	}))
+		panic(panicValue)
+	}), func(ts *httptest.Server) {
+		ts.Config.ErrorLog = log.New(&errorLog, "", 0)
+	})
 	defer cst.close()
 	res, err := cst.c.Get(cst.ts.URL)
 	if err != nil {
@@ -1169,6 +1182,35 @@ func testInterruptWithPanic(t *testing.T, h2 bool) {
 	if err == nil {
 		t.Errorf("client read all successfully; want some error")
 	}
+	wantStackLogged := panicValue != nil && panicValue != ErrAbortHandler
+	errorLog.Lock()
+	gotLog := errorLog.String()
+	if !wantStackLogged {
+		if gotLog == "" {
+			return
+		}
+		if h2 {
+			t.Skip("TODO: make http2.Server respect ErrAbortHandler")
+		}
+		t.Fatalf("want no log output; got: %s", gotLog)
+	}
+	if gotLog == "" {
+		t.Fatalf("wanted a stack trace logged; got nothing")
+	}
+	if !strings.Contains(gotLog, "created by ") && strings.Count(gotLog, "\n") < 6 {
+		t.Errorf("output doesn't look like a panic stack trace. Got: %s", gotLog)
+	}
+}
+
+type lockedBytesBuffer struct {
+	sync.Mutex
+	bytes.Buffer
+}
+
+func (b *lockedBytesBuffer) Write(p []byte) (int, error) {
+	b.Lock()
+	defer b.Unlock()
+	return b.Buffer.Write(p)
 }
 
 // Issue 15366