Move test into test/std subdirectory.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@224658 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/utilities/utility/exchange/exchange.pass.cpp

@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// utilities
+
+// exchange
+
+#include <utility>
+#include <cassert>
+#include <string>
+
+int main()
+{
+#if _LIBCPP_STD_VER > 11
+    {
+    int v = 12;
+    assert ( std::exchange ( v, 23 ) == 12 );
+    assert ( v == 23 );
+    assert ( std::exchange ( v, 67.2 ) == 23 );
+    assert ( v == 67 );
+
+    assert ((std::exchange<int, float> ( v, {} )) == 67 );
+    assert ( v == 0 );
+    
+    }
+
+    {
+    bool b = false;
+    assert ( !std::exchange ( b, true ));
+    assert ( b );
+    }
+
+    {
+    const std::string s1 ( "Hi Mom!" );
+    const std::string s2 ( "Yo Dad!" );
+    std::string s3 = s1; // Mom
+    assert ( std::exchange ( s3, s2 ) == s1 );
+    assert ( s3 == s2 );
+    assert ( std::exchange ( s3, "Hi Mom!" ) == s2 );
+    assert ( s3 == s1 );
+
+    s3 = s2; // Dad
+    assert ( std::exchange ( s3, {} ) == s2 );
+    assert ( s3.size () == 0 );
+    
+    s3 = s2; // Dad
+    assert ( std::exchange ( s3, "" ) == s2 );
+    assert ( s3.size () == 0 );
+    }
+
+#endif
+}