diff -r 7f17c67b5bf6 Lib/idlelib/RstripExtension.py
--- a/Lib/idlelib/RstripExtension.py	Sun Jul 07 17:35:11 2013 +0200
+++ b/Lib/idlelib/RstripExtension.py	Mon Jul 08 00:35:56 2013 -0400
@@ -27,3 +27,8 @@
             text.delete('%i.%i' % (cur, cut), '%i.0 lineend' % cur)
 
         undo.undo_block_stop()
+
+if __name__ == "__main__":
+    from test import support; support.use_resources = ['gui']
+    import unittest
+    unittest.main('idlelib.idle_test.test_rstrip', verbosity=2, exit=False)
diff -r 7f17c67b5bf6 Lib/idlelib/idle_test/mock_idle.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/idlelib/idle_test/mock_idle.py	Mon Jul 08 00:35:56 2013 -0400
@@ -0,0 +1,18 @@
+from idlelib.idle_test.mock_tk import Text
+
+class Editor:
+    """Mock class that imitates tkinter text widget"""
+    def __init__(self):
+        self.text = Text()
+        self.undo = mockUndoDelegator()
+    
+    def get_selection_indices(self):
+    	first = self.text.index('1.0')
+    	last = self.text.index('end')
+    	return first, last
+
+class mockUndoDelegator:
+	def undo_block_start(*args):
+		pass
+	def undo_block_stop(*args):
+		pass
diff -r 7f17c67b5bf6 Lib/idlelib/idle_test/test_rstrip.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/idlelib/idle_test/test_rstrip.py	Mon Jul 08 00:35:56 2013 -0400
@@ -0,0 +1,30 @@
+import unittest
+import idlelib.RstripExtension as rs
+from idlelib.idle_test.mock_idle import Editor
+
+class rstripTest(unittest.TestCase):
+
+    def test_rstrip(self):
+        self.editor = Editor()
+        self.text = self.editor.text
+        self.rstrip = rs.RstripExtension(self.editor)
+
+        self.text.insert('1.0', """Line with an ending tab    
+            Line ending in 5 spaces     
+            Linewithnospaces
+                indented line
+                indented line with trailing space """)
+
+        # The text widget adds a \n at the end of the text area, even
+        # when it holds no text
+        _expectedtext = ("""Line with an ending tab
+            Line ending in 5 spaces
+            Linewithnospaces
+                indented line
+                indented line with trailing space\n""")
+
+        self.rstrip.do_rstrip()
+        self.assertEqual(self.text.get('1.0','end'), _expectedtext)
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2, exit=2)