diff -r 537bd43851a8 Lib/test/test_shutil.py
--- a/Lib/test/test_shutil.py	Sun May 02 15:44:54 2010 -0400
+++ b/Lib/test/test_shutil.py	Wed May 05 17:55:37 2010 -0400
@@ -367,8 +367,113 @@
         finally:
             shutil.rmtree(TESTFN, ignore_errors=True)
 
+
+class TestCopyFile(unittest.TestCase):
+
+    _delete = False
+
+    class Faux(object):
+        _entered = False
+        _exited_with = None
+        _raised = False
+        def __init__(self, raise_in_exit=False, suppress_at_exit=True):
+            self._raise_in_exit = raise_in_exit
+            self._suppress_at_exit = suppress_at_exit
+        def read(self, *args):
+            return ''
+        def __enter__(self):
+            self._entered = True
+        def __exit__(self, exc_type, exc_val, exc_tb):
+            self._exited_with = exc_type, exc_val, exc_tb
+            if self._raise_in_exit:
+                self._raised = True
+                raise IOError("Cannot close")
+            return self._suppress_at_exit
+
+    def tearDown(self):
+        if self._delete:
+            del shutil.open
+
+    def _set_shutil_open(self, func):
+        shutil.open = func
+        self._delete = True
+ 
+    def test_w_source_open_fails(self):
+        def _open(filename, mode='r'):
+            if filename == 'srcfile':
+                raise IOError('Cannot open "srcfile"')
+            assert 0  # shouldn't reach here.
+
+        self._set_shutil_open(_open)
+
+        self.assertRaises(IOError, shutil.copyfile, 'srcfile', 'destfile')
+ 
+    def test_w_dest_open_fails(self):
+
+        srcfile = self.Faux()
+
+        def _open(filename, mode='r'):
+            if filename == 'srcfile':
+                return srcfile
+            if filename == 'destfile':
+                raise IOError('Cannot open "destfile"')
+            assert 0  # shouldn't reach here.
+
+        self._set_shutil_open(_open)
+
+        shutil.copyfile('srcfile', 'destfile')
+        self.failUnless(srcfile._entered)
+        self.failUnless(srcfile._exited_with[0] is IOError)
+        self.assertEqual(srcfile._exited_with[1].args,
+                         ('Cannot open "destfile"',))
+ 
+    def test_w_dest_close_fails(self):
+
+        srcfile = self.Faux()
+        destfile = self.Faux(True)
+
+        def _open(filename, mode='r'):
+            if filename == 'srcfile':
+                return srcfile
+            if filename == 'destfile':
+                return destfile
+            assert 0  # shouldn't reach here.
+
+        self._set_shutil_open(_open)
+
+        shutil.copyfile('srcfile', 'destfile')
+        self.failUnless(srcfile._entered)
+        self.failUnless(destfile._entered)
+        self.failUnless(destfile._raised)
+        self.failUnless(srcfile._exited_with[0] is IOError)
+        self.assertEqual(srcfile._exited_with[1].args,
+                         ('Cannot close',))
+ 
+    def test_w_source_close_fails(self):
+
+        srcfile = self.Faux(True)
+        destfile = self.Faux()
+
+        def _open(filename, mode='r'):
+            if filename == 'srcfile':
+                return srcfile
+            if filename == 'destfile':
+                return destfile
+            assert 0  # shouldn't reach here.
+
+        self._set_shutil_open(_open)
+
+        self.assertRaises(IOError,
+                          shutil.copyfile, 'srcfile', 'destfile')
+        self.failUnless(srcfile._entered)
+        self.failUnless(destfile._entered)
+        self.failIf(destfile._raised)
+        self.failUnless(srcfile._exited_with[0] is None)
+        self.failUnless(srcfile._raised)
+
+
 def test_main():
-    test_support.run_unittest(TestShutil, TestMove)
+    test_support.run_unittest(TestShutil, TestMove, TestCopyFile)
 
 if __name__ == '__main__':
     test_main()