1 files changed, 48 insertions, 0 deletions
diff --git a/test/libcxx/strings/basic.string/string.modifiers/clear_and_shrink_db1.pass.cpp b/test/libcxx/strings/basic.string/string.modifiers/clear_and_shrink_db1.pass.cpp
new file mode 100644
index 000000000000..920c0d185261
--- /dev/null
+++ b/test/libcxx/strings/basic.string/string.modifiers/clear_and_shrink_db1.pass.cpp
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <string>
+
+// Call __clear_and_shrink() and ensure string invariants hold
+
+#if _LIBCPP_DEBUG >= 1
+
+#define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::exit(0))
+
+#include <string>
+#include <cassert>
+
+int main()
+{
+    std::string l = "Long string so that allocation definitely, for sure, absolutely happens. Probably.";
+    std::string s = "short";
+
+    assert(l.__invariants());
+    assert(s.__invariants());
+
+    s.__clear_and_shrink();
+    assert(s.__invariants());
+    assert(s.size() == 0);
+
+    {
+    std::string::size_type cap = l.capacity();
+    l.__clear_and_shrink();
+    assert(l.__invariants());
+    assert(l.size() == 0);
+    assert(l.capacity() < cap);
+    }
+}
+
+#else
+
+int main()
+{
+}
+
+#endif