diff --git a/unittests/ADT/SmallStringTest.cpp b/unittests/ADT/SmallStringTest.cpp
new file mode 100644
index 00000000000..188397476ff
--- /dev/null
+++ b/unittests/ADT/SmallStringTest.cpp
@@ -0,0 +1,64 @@
+//===- llvm/unittest/ADT/SmallStringTest.cpp ------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// SmallString unit tests.
+//
+//===----------------------------------------------------------------------===//
+
+#include "gtest/gtest.h"
+#include "llvm/ADT/SmallString.h"
+#include <stdarg.h>
+#include <climits>
+#include <cstring>
+
+using namespace llvm;
+
+namespace {
+
+// Test fixture class
+class SmallStringTest : public testing::Test {
+protected:
+  typedef SmallString<40> StringType;
+
+  StringType theString;
+
+  void assertEmpty(StringType & v) {
+    // Size tests
+    EXPECT_EQ(0u, v.size());
+    EXPECT_TRUE(v.empty());
+    // Iterator tests
+    EXPECT_TRUE(v.begin() == v.end());
+  }
+};
+
+// New string test.
+TEST_F(SmallStringTest, EmptyStringTest) {
+  SCOPED_TRACE("EmptyStringTest");
+  assertEmpty(theString);
+  EXPECT_TRUE(theString.rbegin() == theString.rend());
+}
+
+TEST_F(SmallStringTest, AppendUINT64_MAX) {
+  SCOPED_TRACE("AppendUINT64_MAX");
+  theString.clear();
+  assertEmpty(theString);
+  theString.append_uint(UINT64_MAX);
+  EXPECT_TRUE(0 == strcmp(theString.c_str(),"18446744073709551615"));
+}
+
+TEST_F(SmallStringTest, AppendINT64_MIN) {
+  SCOPED_TRACE("AppendINT64_MIN");
+  theString.clear();
+  assertEmpty(theString);
+  theString.append_sint(INT64_MIN);
+  EXPECT_TRUE(0 == strcmp(theString.c_str(),"-9223372036854775808"));
+}
+
+}
+