diff --git a/Foundation/CPString.j b/Foundation/CPString.j
index 0639bb8b1..7ee5d08b9 100644
--- a/Foundation/CPString.j
+++ b/Foundation/CPString.j
@@ -510,7 +510,7 @@ var CPStringRegexSpecialCharacters = [
 */
 - (BOOL)hasSuffix:(CPString)aString
 {
-    return aString && aString != "" && lastIndexOf(aString) == (length - aString.length);
+    return aString && aString != "" && length >= aString.length && lastIndexOf(aString) == (length - aString.length);
 }
 
 /*!
diff --git a/Tests/Foundation/CPStringTest.j b/Tests/Foundation/CPStringTest.j
index 5470b58e4..cc7455f8f 100644
--- a/Tests/Foundation/CPStringTest.j
+++ b/Tests/Foundation/CPStringTest.j
@@ -233,4 +233,28 @@
         [self assert:testStrings[i][1] equals:[testStrings[i][0] lastPathComponent]];
 }
 
+- (void)testHasPrefix
+{
+    [self assertTrue: ["abc" hasPrefix:"a"]];
+    [self assertTrue: ["abc" hasPrefix:"ab"]];
+    [self assertTrue: ["abc" hasPrefix:"abc"]];
+    [self assertFalse:["abc" hasPrefix:"abcd"]];
+    [self assertFalse:["abc" hasPrefix:"dbc"]];
+    [self assertFalse:["abc" hasPrefix:"bc"]];
+    [self assertFalse:["abc" hasPrefix:"c"]];
+    [self assertFalse:["abc" hasPrefix:""]];
+}
+
+- (void)testHasSuffix
+{
+    [self assertTrue: ["abc" hasSuffix:"c"]];
+    [self assertTrue: ["abc" hasSuffix:"bc"]];
+    [self assertTrue: ["abc" hasSuffix:"abc"]];
+    [self assertFalse:["abc" hasSuffix:"abcd"]];
+    [self assertFalse:["abc" hasSuffix:"ab"]];
+    [self assertFalse:["abc" hasSuffix:"b"]];
+    [self assertFalse:["abc" hasSuffix:"cat"]];
+    [self assertFalse:["abc" hasSuffix:""]];
+}
+
 @end