http: add test for recently fixed HTTP/1.0 keep-alive issue

R=bradfitzgo, rsc, bradfitzwork
CC=golang-dev
https://golang.org/cl/4235056

src/pkg/http/serve_test.go

@@ -365,3 +365,44 @@ func TestIdentityResponse(t *testing.T) {
 			expectedSuffix, string(got))
 	}
 }
+
+// TestServeHTTP10Close verifies that HTTP/1.0 requests won't be kept alive.
+func TestServeHTTP10Close(t *testing.T) {
+	s := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		ServeFile(w, r, "testdata/file")
+	}))
+	defer s.Close()
+
+	conn, err := net.Dial("tcp", "", s.Listener.Addr().String())
+	if err != nil {
+		t.Fatal("dial error:", err)
+	}
+	defer conn.Close()
+
+	_, err = fmt.Fprint(conn, "GET / HTTP/1.0\r\n\r\n")
+	if err != nil {
+		t.Fatal("print error:", err)
+	}
+
+	r := bufio.NewReader(conn)
+	_, err = ReadResponse(r, "GET")
+	if err != nil {
+		t.Fatal("ReadResponse error:", err)
+	}
+
+	success := make(chan bool)
+	go func() {
+		select {
+		case <-time.After(5e9):
+			t.Fatal("body not closed after 5s")
+		case <-success:
+		}
+	}()
+
+	_, err = ioutil.ReadAll(r)
+	if err != nil {
+		t.Fatal("read error:", err)
+	}
+
+	success <- true
+}