Index: Lib/test/test_readline.py
===================================================================
--- Lib/test/test_readline.py	(revision 78631)
+++ Lib/test/test_readline.py	(working copy)
@@ -6,7 +6,9 @@
 why the tests cover only a small subset of the interface.
 """
 import unittest
-from test.test_support import run_unittest, import_module
+from test.test_support import run_unittest, import_module, TESTFN
+import os
+TEMPDIR = os.path.abspath(TESTFN)
 
 # Skip tests if there is no readline module
 readline = import_module('readline')
@@ -36,8 +38,42 @@
         self.assertEqual(readline.get_current_history_length(), 1)
 
 
+class TestHistoryFile (unittest.TestCase):
+    def setUp(self):
+        os.mkdir(TEMPDIR)
+        self.history_file = os.path.join(TEMPDIR, 'history')
+        self.save_history_length = readline.get_history_length()
+        
+    def tearDown(self):
+        if os.path.exists(self.history_file):
+            os.unlink(self.history_file)
+        os.rmdir(TEMPDIR)
+        readline.set_history_length(self.save_history_length)
+
+    def fillHistory(self):
+        readline.clear_history()
+
+        readline.add_history("first line")
+        readline.add_history("second line")
+        readline.add_history("third line")
+        
+    def testWriteCompleteHistory(self):
+        self.fillHistory()
+        readline.write_history_file(self.history_file)
+        readline.clear_history()
+        readline.read_history_file(self.history_file)
+        self.assertEqual(readline.get_current_history_length(), 3)
+
+    def testWritePartHistory(self):
+        self.fillHistory()
+        readline.set_history_length(2)
+        readline.write_history_file(self.history_file)
+        readline.clear_history()
+        readline.read_history_file(self.history_file)
+        self.assertEqual(readline.get_current_history_length(), 2)
+    
 def test_main():
-    run_unittest(TestHistoryManipulation)
+    run_unittest(TestHistoryManipulation, TestHistoryFile)
 
 if __name__ == "__main__":
     test_main()