Update test_wsgiref.py

Author: benediktjohannes

Lib/test/test_wsgiref.py

@@ -858,15 +858,15 @@ def write(self, b):
     def testRaisesControlCharacters(self):
         for c0 in control_characters_c0():
             with self.subTest(c0):
-                base = BaseHandler()
+                base1, base2, base3 = [BaseHandler() for _ in range(3)]
                 statusLegit = '200 OK'
                 statusWithControlCharacters1 = c0
                 headersLegit = [('x', 'y')]
                 headersWithControlCharacters1 = [(c0, 'y')]
                 headersWithControlCharacters2 = [('x', c0)]
-                self.assertRaises(ValueError, base.start_response, c0, headersLegit)
-                self.assertRaises(ValueError, base.start_response, statusLegit, headersWithControlCharacters1)
-                self.assertRaises(ValueError, base.start_response, statusLegit, headersWithControlCharacters2)
+                self.assertRaises(ValueError, base1.start_response, c0, headersLegit)
+                self.assertRaises(ValueError, base2.start_response, statusLegit, headersWithControlCharacters1)
+                self.assertRaises(ValueError, base3.start_response, statusLegit, headersWithControlCharacters2)
 
 
 class TestModule(unittest.TestCase):