diff --git a/src/test/java/org/apache/commons/lang3/text/translate/EntityArraysTest.java b/src/test/java/org/apache/commons/lang3/text/translate/EntityArraysTest.java
index 08c5b3416..7f7a13437 100644
--- a/src/test/java/org/apache/commons/lang3/text/translate/EntityArraysTest.java
+++ b/src/test/java/org/apache/commons/lang3/text/translate/EntityArraysTest.java
@@ -17,6 +17,9 @@
 
 package org.apache.commons.lang3.text.translate;
 
+import java.util.HashSet;
+import java.util.Set;
+
 import junit.framework.TestCase;
 
 /**
@@ -28,4 +31,38 @@ public class EntityArraysTest extends TestCase {
     public void testConstructorExists() {
         new EntityArrays();
     }
+    
+    // LANG-659 - check arrays for duplicate entries
+    public void testHTML40_EXTENDED_ESCAPE(){
+        Set<String> col0 = new HashSet<String>();
+        Set<String> col1 = new HashSet<String>();
+        String [][] sa = EntityArrays.HTML40_EXTENDED_ESCAPE();
+        for(int i =0; i <sa.length; i++){
+            assertTrue("Already added entry 0: "+i+" "+sa[i][0],col0.add(sa[i][0]));
+            assertTrue("Already added entry 1: "+i+" "+sa[i][1],col1.add(sa[i][1]));
+        }
+    }
+    
+   // LANG-658 - check arrays for duplicate entries
+    public void testISO8859_1_ESCAPE(){
+        Set<String> col0 = new HashSet<String>();
+        Set<String> col1 = new HashSet<String>();
+        String [][] sa = EntityArrays.ISO8859_1_ESCAPE();
+        boolean success = true;
+        for(int i =0; i <sa.length; i++){
+            boolean add0 = col0.add(sa[i][0]);
+            boolean add1 = col1.add(sa[i][1]);
+            if (!add0) { 
+                success = false;
+                System.out.println("Already added entry 0: "+i+" "+sa[i][0]+" "+sa[i][1]);
+            }
+            if (!add1) {
+                success = false;
+                System.out.println("Already added entry 1: "+i+" "+sa[i][0]+" "+sa[i][1]);
+            }
+        }
+        assertTrue("One or more errors detected",success);
+    }
+    
+    
 }