diff --git a/Lib/test/test_format.py b/Lib/test/test_format.py
index 88eb61a..7fa950d 100644
--- a/Lib/test/test_format.py
+++ b/Lib/test/test_format.py
@@ -10,9 +10,7 @@
 # they crash python)
 # test on unicode strings as well
 
-overflowok = 1
-
-def testformat(formatstr, args, output=None, limit=None):
+def testformat(formatstr, args, output=None, limit=None, overflowok=False):
     if verbose:
         if output:
             print("%r %% %r =? %r ..." %\
@@ -50,13 +48,19 @@
 
 class FormatTest(unittest.TestCase):
     def test_format(self):
-        global overflowok
-
         testformat("%.1d", (1,), "1")
-        testformat("%.*d", (sys.maxsize,1))  # expect overflow
-        testformat("%.100d", (1,), '0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001')
-        testformat("%#.117x", (1,), '0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001')
-        testformat("%#.118x", (1,), '0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001')
+        testformat("%.*d", (sys.maxsize,1), overflowok=True)  # expect overflow
+        testformat("%.100d", (1,), '00000000000000000000000000000000000000'
+                 '000000000000000000000000000000000000000000000000000000'
+                 '00000001', overflowok=True)
+        testformat("%#.117x", (1,), '0x00000000000000000000000000000000000'
+                 '000000000000000000000000000000000000000000000000000000'
+                 '0000000000000000000000000001',
+                 overflowok=True)
+        testformat("%#.118x", (1,), '0x00000000000000000000000000000000000'
+                 '000000000000000000000000000000000000000000000000000000'
+                 '00000000000000000000000000001',
+                 overflowok=True)
 
         testformat("%f", (1.0,), "1.000000")
         # these are trying to test the limits of the internal magic-number-length
@@ -76,7 +80,6 @@
         testformat("%#.*f", (110, -1.e+100/3.))
         testformat("%#.*F", (110, -1.e+100/3.))
         # Formatting of integers. Overflow is not ok
-        overflowok = 0
         testformat("%x", 10, "a")
         testformat("%x", 100000000000, "174876e800")
         testformat("%o", 10, "12")