diff --git a/src/test/java/org/apache/commons/lang3/StringUtilsTest.java b/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
index 0011f8ad9..e954a1e5b 100644
--- a/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
+++ b/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
@@ -23,10 +23,10 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.Locale;
 
-import org.apache.commons.lang3.text.WordUtils;
-
 import junit.framework.TestCase;
 
+import org.apache.commons.lang3.text.WordUtils;
+
 /**
  * Unit tests {@link org.apache.commons.lang3.StringUtils}.
  *
@@ -1296,7 +1296,7 @@ public class StringUtilsTest extends TestCase {
         assertEquals("  abc", StringUtils.leftPad("abc", 5, ""));
     }
 
-    public void testLength() {
+    public void testLengthString() {
         assertEquals(0, StringUtils.length(null));
         assertEquals(0, StringUtils.length(""));
         assertEquals(0, StringUtils.length(StringUtils.EMPTY));
@@ -1304,6 +1304,22 @@ public class StringUtilsTest extends TestCase {
         assertEquals(1, StringUtils.length(" "));
         assertEquals(8, StringUtils.length("ABCDEFGH"));
     }
+
+    public void testLengthStringBuffer() {
+        assertEquals(0, StringUtils.length(new StringBuffer("")));
+        assertEquals(0, StringUtils.length(new StringBuffer(StringUtils.EMPTY)));
+        assertEquals(1, StringUtils.length(new StringBuffer("A")));
+        assertEquals(1, StringUtils.length(new StringBuffer(" ")));
+        assertEquals(8, StringUtils.length(new StringBuffer("ABCDEFGH")));
+    }
+
+    public void testLengthStringBuilder() {
+        assertEquals(0, StringUtils.length(new StringBuilder("")));
+        assertEquals(0, StringUtils.length(new StringBuilder(StringUtils.EMPTY)));
+        assertEquals(1, StringUtils.length(new StringBuilder("A")));
+        assertEquals(1, StringUtils.length(new StringBuilder(" ")));
+        assertEquals(8, StringUtils.length(new StringBuilder("ABCDEFGH")));
+    }
     
     //-----------------------------------------------------------------------
     public void testCenter_StringInt() {