From 1cc1a490288a558e9aaaad5ea33c081f539074e0 Mon Sep 17 00:00:00 2001
From: Kavya Srinet <kavyasrinet@baidu.com>
Date: Mon, 5 Feb 2018 13:18:41 -0800
Subject: [PATCH] Test case to check if receiver blocks on empty channel

---
 paddle/framework/channel_test.cc | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/paddle/framework/channel_test.cc b/paddle/framework/channel_test.cc
index 444d68498c9676..2f4df767e2b496 100644
--- a/paddle/framework/channel_test.cc
+++ b/paddle/framework/channel_test.cc
@@ -82,6 +82,33 @@ TEST(Channel, ConcurrentSendNonConcurrentReceiveWithSufficientBufferSize) {
   delete ch;
 }
 
+void ReceiveEmptyChannelTest(Channel* ch) {
+  size_t current = 5;
+  std::thread t([&]() {
+    // Read from channel
+    int out;
+    ch->Receive(&out); // should block since channel is empty
+    current = 10;
+  });
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));  // wait 0.1 sec
+  EXPECT_EQ(current, 5U); // the receiver should be blocked since channel is empty
+
+  CloseChannel(ch);
+  t.join();
+  EXPECT_EQ(current, 10U); // when we close the channel, the receiver should unblock
+  delete ch;
+}
+
+TEST(Channel, BufferedReceiveEmptyChannelTest) {
+  auto ch = MakeChannel<size_t>(3);
+  ReceiveEmptyChannelTest(ch);
+}
+
+TEST(Channel, UnBufferedReceiveEmptyChannelTest) {
+  auto ch = MakeChannel<size_t>(0);
+  ReceiveEmptyChannelTest(ch);
+}
+
 TEST(Channel, SimpleUnbufferedChannelTest) {
   auto ch = MakeChannel<int>(0);
   unsigned sum_send = 0;