martian: add content length check in tests

internal/martian/proxy_test.go

@@ -963,6 +963,16 @@ func TestIntegrationConnectUpstreamProxy(t *testing.T) {
 	utr.Respond(299)
 	upstream.RoundTripper = utr
 
+	utm := martiantest.NewModifier()
+
+	// Force the CONNECT request to dial the local TLS server.
+	utm.RequestFunc(func(req *http.Request) {
+		if req.Method == http.MethodConnect && req.ContentLength != -1 {
+			t.Errorf("req.ContentLength: got %d, want -1", req.ContentLength)
+		}
+	})
+	upstream.RequestModifier = utm
+
 	ca, priv, err := mitm.NewAuthority("martian.proxy", "Martian Authority", 2*time.Hour)
 	if err != nil {
 		t.Fatalf("mitm.NewAuthority(): got %v, want no error", err)
@@ -1017,6 +1027,9 @@ func TestIntegrationConnectUpstreamProxy(t *testing.T) {
 	if got, want := res.StatusCode, 200; got != want {
 		t.Fatalf("res.StatusCode: got %d, want %d", got, want)
 	}
+	if res.ContentLength != -1 {
+		t.Errorf("res.ContentLength: got %d, want -1", res.ContentLength)
+	}
 
 	roots := x509.NewCertPool()
 	roots.AddCert(ca)
@@ -1076,6 +1089,10 @@ func TestIntegrationConnectFunc(t *testing.T) {
 	l := newListener(t)
 	p := new(Proxy)
 	p.ConnectFunc = func(req *http.Request) (*http.Response, io.ReadWriteCloser, error) {
+		if req.ContentLength != -1 {
+			t.Errorf("req.ContentLength: got %d, want -1", req.ContentLength)
+		}
+
 		pr, pw := io.Pipe()
 		return newConnectResponse(req), pipeConn{pr, pw}, nil
 	}
@@ -1110,6 +1127,9 @@ func TestIntegrationConnectFunc(t *testing.T) {
 	if got, want := res.StatusCode, 200; got != want {
 		t.Errorf("res.StatusCode: got %d, want %d", got, want)
 	}
+	if res.ContentLength != -1 {
+		t.Errorf("res.ContentLength: got %d, want -1", res.ContentLength)
+	}
 
 	if _, err := conn.Write([]byte("12345")); err != nil {
 		t.Fatalf("conn.Write(): got %v, want no error", err)