diff --git a/solutions/09_strings/strings3.rs b/solutions/09_strings/strings3.rs
index a478e62a..ee6b56af 100644
--- a/solutions/09_strings/strings3.rs
+++ b/solutions/09_strings/strings3.rs
@@ -26,6 +26,7 @@ mod tests {
         assert_eq!(trim_me("Hello!     "), "Hello!");
         assert_eq!(trim_me("  What's up!"), "What's up!");
         assert_eq!(trim_me("   Hola!  "), "Hola!");
+        assert_eq!(trim_me("Hi!"), "Hi!");
     }
 
     #[test]