add a test

src/core/surface/channel_connectivity.c

@@ -78,6 +78,7 @@ typedef struct {
 } state_watcher;
 
 static void delete_state_watcher(state_watcher *w) {
+  GRPC_CHANNEL_INTERNAL_UNREF(w->channel, "watch_connectivity");
   gpr_mu_destroy(&w->mu);
   gpr_free(w);
 }
@@ -117,7 +118,6 @@ static void partly_done(state_watcher *w, int due_to_completion) {
         grpc_channel_get_channel_stack(w->channel));
     grpc_client_channel_del_interested_party(client_channel_elem,
                                              grpc_cq_pollset(w->cq));
-    GRPC_CHANNEL_INTERNAL_UNREF(w->channel, "watch_connectivity");
   }
   gpr_mu_unlock(&w->mu);
   if (due_to_completion) {

test/cpp/end2end/end2end_test.cc

@@ -1076,6 +1076,24 @@ TEST_F(End2endTest, ChannelState) {
   EXPECT_EQ(GRPC_CHANNEL_CONNECTING, channel_->GetState(false));
 }
 
+// Takes 10s.
+TEST_F(End2endTest, ChannelStateTimeout) {
+  int port = grpc_pick_unused_port_or_die();
+  std::ostringstream server_address;
+  server_address << "127.0.0.1:" << port;
+  // Channel to non-existing server
+  auto channel = CreateChannel(server_address.str(), InsecureCredentials());
+  // Start IDLE
+  EXPECT_EQ(GRPC_CHANNEL_IDLE, channel->GetState(true));
+
+  auto state = GRPC_CHANNEL_IDLE;
+  for (int i = 0; i < 10; i++) {
+    channel->WaitForStateChange(state, std::chrono::system_clock::now() +
+                                           std::chrono::milliseconds(1000));
+    state = channel->GetState(false);
+  }
+}
+
 // Talking to a non-existing service.
 TEST_F(End2endTest, NonExistingService) {
   ResetChannel();