diff --git a/unittests/ADT/SmallStringTest.cpp b/unittests/ADT/SmallStringTest.cpp
index 099d815..660ac44 100644
--- a/unittests/ADT/SmallStringTest.cpp
+++ b/unittests/ADT/SmallStringTest.cpp
@@ -44,5 +44,153 @@
   EXPECT_TRUE(theString.rbegin() == theString.rend());
 }
 
+TEST_F(SmallStringTest, AssignRepeated) {
+  theString.assign(3, 'a');
+  EXPECT_EQ(3u, theString.size());
+  EXPECT_STREQ("aaa", theString.c_str());
 }
 
+TEST_F(SmallStringTest, AssignIterPair) {
+  StringRef abc = "abc";
+  theString.assign(abc.begin(), abc.end());
+  EXPECT_EQ(3u, theString.size());
+  EXPECT_STREQ("abc", theString.c_str());
+}
+
+TEST_F(SmallStringTest, AssignStringRef) {
+  StringRef abc = "abc";
+  theString.assign(abc);
+  EXPECT_EQ(3u, theString.size());
+  EXPECT_STREQ("abc", theString.c_str());
+}
+
+TEST_F(SmallStringTest, AssignSmallVector) {
+  StringRef abc = "abc";
+  SmallVector<char, 10> abcVec(abc.begin(), abc.end());
+  theString.assign(abcVec);
+  EXPECT_EQ(3u, theString.size());
+  EXPECT_STREQ("abc", theString.c_str());
+}
+
+TEST_F(SmallStringTest, AppendIterPair) {
+  StringRef abc = "abc";
+  theString.append(abc.begin(), abc.end());
+  theString.append(abc.begin(), abc.end());
+  EXPECT_EQ(6u, theString.size());
+  EXPECT_STREQ("abcabc", theString.c_str());
+}
+
+TEST_F(SmallStringTest, AppendStringRef) {
+  StringRef abc = "abc";
+  theString.append(abc);
+  theString.append(abc);
+  EXPECT_EQ(6u, theString.size());
+  EXPECT_STREQ("abcabc", theString.c_str());
+}
+
+TEST_F(SmallStringTest, AppendSmallVector) {
+  StringRef abc = "abc";
+  SmallVector<char, 10> abcVec(abc.begin(), abc.end());
+  theString.append(abcVec);
+  theString.append(abcVec);
+  EXPECT_EQ(6u, theString.size());
+  EXPECT_STREQ("abcabc", theString.c_str());
+}
+
+TEST_F(SmallStringTest, Substr) {
+  theString = "hello";
+  EXPECT_EQ("lo", theString.substr(3));
+  EXPECT_EQ("", theString.substr(100));
+  EXPECT_EQ("hello", theString.substr(0, 100));
+  EXPECT_EQ("o", theString.substr(4, 10));
+}
+
+TEST_F(SmallStringTest, Slice) {
+  theString = "hello";
+  EXPECT_EQ("l", theString.slice(2, 3));
+  EXPECT_EQ("ell", theString.slice(1, 4));
+  EXPECT_EQ("llo", theString.slice(2, 100));
+  EXPECT_EQ("", theString.slice(2, 1));
+  EXPECT_EQ("", theString.slice(10, 20));
+}
+
+TEST_F(SmallStringTest, Find) {
+  theString = "hello";
+  EXPECT_EQ(2U, theString.find('l'));
+  EXPECT_EQ(StringRef::npos, theString.find('z'));
+  EXPECT_EQ(StringRef::npos, theString.find("helloworld"));
+  EXPECT_EQ(0U, theString.find("hello"));
+  EXPECT_EQ(1U, theString.find("ello"));
+  EXPECT_EQ(StringRef::npos, theString.find("zz"));
+  EXPECT_EQ(2U, theString.find("ll", 2));
+  EXPECT_EQ(StringRef::npos, theString.find("ll", 3));
+  EXPECT_EQ(0U, theString.find(""));
+
+  EXPECT_EQ(3U, theString.rfind('l'));
+  EXPECT_EQ(StringRef::npos, theString.rfind('z'));
+  EXPECT_EQ(StringRef::npos, theString.rfind("helloworld"));
+  EXPECT_EQ(0U, theString.rfind("hello"));
+  EXPECT_EQ(1U, theString.rfind("ello"));
+  EXPECT_EQ(StringRef::npos, theString.rfind("zz"));
+
+  EXPECT_EQ(2U, theString.find_first_of('l'));
+  EXPECT_EQ(1U, theString.find_first_of("el"));
+  EXPECT_EQ(StringRef::npos, theString.find_first_of("xyz"));
+
+  EXPECT_EQ(1U, theString.find_first_not_of('h'));
+  EXPECT_EQ(4U, theString.find_first_not_of("hel"));
+  EXPECT_EQ(StringRef::npos, theString.find_first_not_of("hello"));
+
+  theString = "hellx xello hell ello world foo bar hello";
+  EXPECT_EQ(36U, theString.find("hello"));
+  EXPECT_EQ(28U, theString.find("foo"));
+  EXPECT_EQ(12U, theString.find("hell", 2));
+  EXPECT_EQ(0U, theString.find(""));
+}
+
+TEST_F(SmallStringTest, Count) {
+  theString = "hello";
+  EXPECT_EQ(2U, theString.count('l'));
+  EXPECT_EQ(1U, theString.count('o'));
+  EXPECT_EQ(0U, theString.count('z'));
+  EXPECT_EQ(0U, theString.count("helloworld"));
+  EXPECT_EQ(1U, theString.count("hello"));
+  EXPECT_EQ(1U, theString.count("ello"));
+  EXPECT_EQ(0U, theString.count("zz"));
+}
+
+TEST(StringRefTest, Comparisons) {
+  EXPECT_EQ(-1, SmallString<10>("aab").compare("aad"));
+  EXPECT_EQ( 0, SmallString<10>("aab").compare("aab"));
+  EXPECT_EQ( 1, SmallString<10>("aab").compare("aaa"));
+  EXPECT_EQ(-1, SmallString<10>("aab").compare("aabb"));
+  EXPECT_EQ( 1, SmallString<10>("aab").compare("aa"));
+  EXPECT_EQ( 1, SmallString<10>("\xFF").compare("\1"));
+
+  EXPECT_EQ(-1, SmallString<10>("AaB").compare_lower("aAd"));
+  EXPECT_EQ( 0, SmallString<10>("AaB").compare_lower("aab"));
+  EXPECT_EQ( 1, SmallString<10>("AaB").compare_lower("AAA"));
+  EXPECT_EQ(-1, SmallString<10>("AaB").compare_lower("aaBb"));
+  EXPECT_EQ( 1, SmallString<10>("AaB").compare_lower("aA"));
+  EXPECT_EQ( 1, SmallString<10>("\xFF").compare_lower("\1"));
+
+  EXPECT_EQ(-1, SmallString<10>("aab").compare_numeric("aad"));
+  EXPECT_EQ( 0, SmallString<10>("aab").compare_numeric("aab"));
+  EXPECT_EQ( 1, SmallString<10>("aab").compare_numeric("aaa"));
+  EXPECT_EQ(-1, SmallString<10>("aab").compare_numeric("aabb"));
+  EXPECT_EQ( 1, SmallString<10>("aab").compare_numeric("aa"));
+  EXPECT_EQ(-1, SmallString<10>("1").compare_numeric("10"));
+  EXPECT_EQ( 0, SmallString<10>("10").compare_numeric("10"));
+  EXPECT_EQ( 0, SmallString<10>("10a").compare_numeric("10a"));
+  EXPECT_EQ( 1, SmallString<10>("2").compare_numeric("1"));
+  EXPECT_EQ( 0, SmallString<10>("llvm_v1i64_ty").compare_numeric("llvm_v1i64_ty"));
+  EXPECT_EQ( 1, SmallString<10>("\xFF").compare_numeric("\1"));
+  EXPECT_EQ( 1, SmallString<10>("V16").compare_numeric("V1_q0"));
+  EXPECT_EQ(-1, SmallString<10>("V1_q0").compare_numeric("V16"));
+  EXPECT_EQ(-1, SmallString<10>("V8_q0").compare_numeric("V16"));
+  EXPECT_EQ( 1, SmallString<10>("V16").compare_numeric("V8_q0"));
+  EXPECT_EQ(-1, SmallString<10>("V1_q0").compare_numeric("V8_q0"));
+  EXPECT_EQ( 1, SmallString<10>("V8_q0").compare_numeric("V1_q0"));
+}
+
+}