diff --git a/tests/stringbuffer-misc/main.java b/tests/stringbuffer-misc/main.java
index 386149e..1412122 100644
--- a/tests/stringbuffer-misc/main.java
+++ b/tests/stringbuffer-misc/main.java
@@ -48,6 +48,9 @@ public static void main(String[] args) {
         errorCount += checker("sb1.length(35)", 35, sb1.length());
         
         sb1 = new StringBuffer("ABCDEFGHIJKLMNOPQRSTUVWXYZxyz");        
+        sb1.reverse();
+        errorCount += checker("sb1.reverse()", "zyxZYXWVUTSRQPONMLKJIHGFEDCBA", sb1.toString());
+        sb1.reverse();    
         StringBuffer sb2 = new StringBuffer("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
         System.out.printf("sb1: %s\n", sb1);
         System.out.printf("sb2: %s\n", sb2);
diff --git a/tests/stringbuilder-misc/main.java b/tests/stringbuilder-misc/main.java
index 70ba4fe..69d546b 100644
--- a/tests/stringbuilder-misc/main.java
+++ b/tests/stringbuilder-misc/main.java
@@ -47,7 +47,10 @@ public static void main(String[] args) {
         errorCount += checker("sb1.capacity(42)", 42, sb1.capacity());
         errorCount += checker("sb1.length(35)", 35, sb1.length());
         
-        sb1 = new StringBuilder("ABCDEFGHIJKLMNOPQRSTUVWXYZxyz");        
+        sb1 = new StringBuilder("ABCDEFGHIJKLMNOPQRSTUVWXYZxyz");
+        sb1.reverse();
+        errorCount += checker("sb1.reverse()", "zyxZYXWVUTSRQPONMLKJIHGFEDCBA", sb1.toString());
+        sb1.reverse();    
         StringBuilder sb2 = new StringBuilder("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
         System.out.printf("sb1: %s\n", sb1);
         System.out.printf("sb2: %s\n", sb2);