Issue #15784: Modify OSError.__str__() to better distinguish between
errno error numbers and Windows error numbers.
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
index 55e9db3..413f4dd 100644
--- a/Lib/test/test_exceptions.py
+++ b/Lib/test/test_exceptions.py
@@ -216,14 +216,14 @@
             self.assertEqual(w.winerror, 3)
             self.assertEqual(w.strerror, 'foo')
             self.assertEqual(w.filename, 'bar')
-            self.assertEqual(str(w), "[Error 3] foo: 'bar'")
+            self.assertEqual(str(w), "[WinError 3] foo: 'bar'")
             # Unknown win error becomes EINVAL (22)
             w = OSError(0, 'foo', None, 1001)
             self.assertEqual(w.errno, 22)
             self.assertEqual(w.winerror, 1001)
             self.assertEqual(w.strerror, 'foo')
             self.assertEqual(w.filename, None)
-            self.assertEqual(str(w), "[Error 1001] foo")
+            self.assertEqual(str(w), "[WinError 1001] foo")
             # Non-numeric "errno"
             w = OSError('bar', 'foo')
             self.assertEqual(w.errno, 'bar')