diff --git a/AK/Tests/TestString.cpp b/AK/Tests/TestString.cpp
index fb26395a09..aefe1b908a 100644
--- a/AK/Tests/TestString.cpp
+++ b/AK/Tests/TestString.cpp
@@ -4,16 +4,33 @@ int main()
 {
     ASSERT(String().is_null());
     ASSERT(String().is_empty());
+    ASSERT(!String().characters());
 
     ASSERT(!String("").is_null());
     ASSERT(String("").is_empty());
+    ASSERT(String("").characters());
+
+    ASSERT(String("").impl() == String::empty().impl());
 
     String test_string = "ABCDEF";
     ASSERT(!test_string.is_empty());
     ASSERT(!test_string.is_null());
     ASSERT(test_string.length() == 6);
     ASSERT(test_string.length() == strlen(test_string.characters()));
+    ASSERT(test_string.characters());
     ASSERT(!strcmp(test_string.characters(), "ABCDEF"));
 
+    ASSERT(test_string == "ABCDEF");
+    ASSERT(test_string != "ABCDE");
+    ASSERT(test_string != "ABCDEFG");
+
+    auto test_string_copy = test_string;
+    ASSERT(test_string == test_string_copy);
+    ASSERT(test_string.characters() == test_string_copy.characters());
+
+    auto test_string_move = move(test_string_copy);
+    ASSERT(test_string == test_string_move);
+    ASSERT(test_string_copy.is_null());
+
     return 0;
 }