Issue #20557: Use specific asserts in io tests.
diff --git a/Lib/test/test_bufio.py b/Lib/test/test_bufio.py
index 108b1e1..d6b12e3 100644
--- a/Lib/test/test_bufio.py
+++ b/Lib/test/test_bufio.py
@@ -34,7 +34,7 @@
             line = f.readline()
             self.assertEqual(line, s)
             line = f.readline()
-            self.assertTrue(not line) # Must be at EOF
+            self.assertFalse(line) # Must be at EOF
             f.close()
         finally:
             support.unlink(support.TESTFN)