diff --git a/unittests/ADT/StringRefTest.cpp b/unittests/ADT/StringRefTest.cpp
index 8364eac..d910843 100644
--- a/unittests/ADT/StringRefTest.cpp
+++ b/unittests/ADT/StringRefTest.cpp
@@ -245,6 +245,12 @@
   EXPECT_EQ(StringRef::npos, Str.find("zz"));
   EXPECT_EQ(2U, Str.find("ll", 2));
   EXPECT_EQ(StringRef::npos, Str.find("ll", 3));
+  EXPECT_EQ(0U, Str.find(""));
+  StringRef LongStr("hellx xello hell ello world foo bar hello");
+  EXPECT_EQ(36U, LongStr.find("hello"));
+  EXPECT_EQ(28U, LongStr.find("foo"));
+  EXPECT_EQ(12U, LongStr.find("hell", 2));
+  EXPECT_EQ(0U, LongStr.find(""));
 
   EXPECT_EQ(3U, Str.rfind('l'));
   EXPECT_EQ(StringRef::npos, Str.rfind('z'));