diff --git a/libutils/String16_test.cpp b/libutils/String16_test.cpp
index f1f24c3..2505f44 100644
--- a/libutils/String16_test.cpp
+++ b/libutils/String16_test.cpp
@@ -215,4 +215,16 @@
     EXPECT_TRUE(tmp.isStaticString());
 }
 
+TEST(String16Test, OverreadUtf8Conversion) {
+    char tmp[] = {'a', static_cast<char>(0xe0), '\0'};
+    String16 another(tmp);
+    EXPECT_TRUE(another.size() == 0);
+}
+
+TEST(String16Test, ValidUtf8Conversion) {
+    String16 another("abcdef");
+    EXPECT_EQ(6U, another.size());
+    EXPECT_STR16EQ(another, u"abcdef");
+}
+
 }  // namespace android
diff --git a/libutils/String8_test.cpp b/libutils/String8_test.cpp
index 3947a5f..9efcc6f 100644
--- a/libutils/String8_test.cpp
+++ b/libutils/String8_test.cpp
@@ -96,4 +96,9 @@
     EXPECT_EQ(10U, string8.length());
 }
 
+TEST_F(String8Test, ValidUtf16Conversion) {
+    char16_t tmp[] = u"abcdef";
+    String8 valid = String8(String16(tmp));
+    EXPECT_STREQ(valid, "abcdef");
+}
 }