[futures.promise]. Depends on rvalue-ref support to work 100%.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@112388 91177308-0d34-0410-b5e6-96231b3b80d8

test/thread/futures/futures.promise/move_assign.pass.cpp

@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <future>
+
+// class promise<R>
+
+// promise& operator=(promise&& rhs);
+
+#include <future>
+#include <cassert>
+
+#include "../test_allocator.h"
+
+int main()
+{
+#ifdef _LIBCPP_MOVE
+    assert(test_alloc_base::count == 0);
+    {
+        std::promise<int> p0(std::allocator_arg, test_allocator<int>());
+        std::promise<int> p(std::allocator_arg, test_allocator<int>());
+        assert(test_alloc_base::count == 2);
+        p = std::move(p0);
+        assert(test_alloc_base::count == 1);
+        std::future<int> f = p.get_future();
+        assert(test_alloc_base::count == 1);
+        assert(f.valid());
+        try
+        {
+            f = p0.get_future();
+            assert(false);
+        }
+        catch (const std::future_error& e)
+        {
+            assert(e.code() == make_error_code(std::future_errc::no_state));
+        }
+        assert(test_alloc_base::count == 1);
+    }
+    assert(test_alloc_base::count == 0);
+    {
+        std::promise<int&> p0(std::allocator_arg, test_allocator<int>());
+        std::promise<int&> p(std::allocator_arg, test_allocator<int>());
+        assert(test_alloc_base::count == 2);
+        p = std::move(p0);
+        assert(test_alloc_base::count == 1);
+        std::future<int&> f = p.get_future();
+        assert(test_alloc_base::count == 1);
+        assert(f.valid());
+        try
+        {
+            f = p0.get_future();
+            assert(false);
+        }
+        catch (const std::future_error& e)
+        {
+            assert(e.code() == make_error_code(std::future_errc::no_state));
+        }
+        assert(test_alloc_base::count == 1);
+    }
+    assert(test_alloc_base::count == 0);
+    {
+        std::promise<void> p0(std::allocator_arg, test_allocator<void>());
+        std::promise<void> p(std::allocator_arg, test_allocator<void>());
+        assert(test_alloc_base::count == 2);
+        p = std::move(p0);
+        assert(test_alloc_base::count == 1);
+        std::future<void> f = p.get_future();
+        assert(test_alloc_base::count == 1);
+        assert(f.valid());
+        try
+        {
+            f = p0.get_future();
+            assert(false);
+        }
+        catch (const std::future_error& e)
+        {
+            assert(e.code() == make_error_code(std::future_errc::no_state));
+        }
+        assert(test_alloc_base::count == 1);
+    }
+    assert(test_alloc_base::count == 0);
+#endif  // _LIBCPP_MOVE
+}