Index: Lib/test/test_complex.py
===================================================================
--- Lib/test/test_complex.py	(revision 83227)
+++ Lib/test/test_complex.py	(working copy)
@@ -506,6 +506,16 @@
         self.assertEqual(format(z, '-'), str(z))
         self.assertEqual(format(z, '<'), str(z))
         self.assertEqual(format(z, '10'), str(z))
+        z = complex(0.0, 3.0)
+        self.assertEqual(format(z, ''), str(z))
+        self.assertEqual(format(z, '-'), str(z))
+        self.assertEqual(format(z, '<'), str(z))
+        self.assertEqual(format(z, '10'), str(z))
+        z = complex(-0.0, 2.0)
+        self.assertEqual(format(z, ''), str(z))
+        self.assertEqual(format(z, '-'), str(z))
+        self.assertEqual(format(z, '<'), str(z))
+        self.assertEqual(format(z, '10'), str(z))
 
         self.assertEqual(format(1+3j, 'g'), '1+3j')
         self.assertEqual(format(3j, 'g'), '0+3j')