--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/unittests/Support/TaskQueueTest.cpp	Wed Aug 14 19:46:37 2019 +0900
@@ -0,0 +1,107 @@
+//========- unittests/Support/TaskQueue.cpp - TaskQueue.h tests ------========//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Config/llvm-config.h"
+
+#if LLVM_ENABLE_THREADS
+
+#include "llvm/Support/TaskQueue.h"
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+class TaskQueueTest : public testing::Test {
+protected:
+  TaskQueueTest() {}
+};
+
+TEST_F(TaskQueueTest, OrderedFutures) {
+  ThreadPool TP(1);
+  TaskQueue TQ(TP);
+  std::atomic<int> X{ 0 };
+  std::atomic<int> Y{ 0 };
+  std::atomic<int> Z{ 0 };
+
+  std::mutex M1, M2, M3;
+  std::unique_lock<std::mutex> L1(M1);
+  std::unique_lock<std::mutex> L2(M2);
+  std::unique_lock<std::mutex> L3(M3);
+
+  std::future<void> F1 = TQ.async([&] {
+    std::unique_lock<std::mutex> Lock(M1);
+    ++X;
+  });
+  std::future<void> F2 = TQ.async([&] {
+    std::unique_lock<std::mutex> Lock(M2);
+    ++Y;
+  });
+  std::future<void> F3 = TQ.async([&] {
+    std::unique_lock<std::mutex> Lock(M3);
+    ++Z;
+  });
+
+  L1.unlock();
+  F1.wait();
+  ASSERT_EQ(1, X);
+  ASSERT_EQ(0, Y);
+  ASSERT_EQ(0, Z);
+
+  L2.unlock();
+  F2.wait();
+  ASSERT_EQ(1, X);
+  ASSERT_EQ(1, Y);
+  ASSERT_EQ(0, Z);
+
+  L3.unlock();
+  F3.wait();
+  ASSERT_EQ(1, X);
+  ASSERT_EQ(1, Y);
+  ASSERT_EQ(1, Z);
+}
+
+TEST_F(TaskQueueTest, UnOrderedFutures) {
+  ThreadPool TP(1);
+  TaskQueue TQ(TP);
+  std::atomic<int> X{ 0 };
+  std::atomic<int> Y{ 0 };
+  std::atomic<int> Z{ 0 };
+  std::mutex M;
+
+  std::unique_lock<std::mutex> Lock(M);
+
+  std::future<void> F1 = TQ.async([&] { ++X; });
+  std::future<void> F2 = TQ.async([&] { ++Y; });
+  std::future<void> F3 = TQ.async([&M, &Z] {
+    std::unique_lock<std::mutex> Lock(M);
+    ++Z;
+  });
+
+  F2.wait();
+  ASSERT_EQ(1, X);
+  ASSERT_EQ(1, Y);
+  ASSERT_EQ(0, Z);
+
+  Lock.unlock();
+
+  F3.wait();
+  ASSERT_EQ(1, X);
+  ASSERT_EQ(1, Y);
+  ASSERT_EQ(1, Z);
+}
+
+TEST_F(TaskQueueTest, FutureWithReturnValue) {
+  ThreadPool TP(1);
+  TaskQueue TQ(TP);
+  std::future<std::string> F1 = TQ.async([&] { return std::string("Hello"); });
+  std::future<int> F2 = TQ.async([&] { return 42; });
+
+  ASSERT_EQ(42, F2.get());
+  ASSERT_EQ("Hello", F1.get());
+}
+#endif