Skips console open_fd tests when we don't have real consoles.

Lib/test/test_winconsoleio.py

@@ -25,26 +25,29 @@ class WindowsConsoleIOTests(unittest.TestCase):
         self.assertFalse(issubclass(ConIO, io.TextIOBase))
 
     def test_open_fd(self):
-        f = ConIO(0)
-        self.assertTrue(f.readable())
-        self.assertFalse(f.writable())
-        self.assertEqual(0, f.fileno())
-        f.close()   # multiple close should not crash
-        f.close()
+        if sys.stdin.fileno() == 0:
+            f = ConIO(0)
+            self.assertTrue(f.readable())
+            self.assertFalse(f.writable())
+            self.assertEqual(0, f.fileno())
+            f.close()   # multiple close should not crash
+            f.close()
 
-        f = ConIO(1, 'w')
-        self.assertFalse(f.readable())
-        self.assertTrue(f.writable())
-        self.assertEqual(1, f.fileno())
-        f.close()
-        f.close()
+        if sys.stdout.fileno() == 1:
+            f = ConIO(1, 'w')
+            self.assertFalse(f.readable())
+            self.assertTrue(f.writable())
+            self.assertEqual(1, f.fileno())
+            f.close()
+            f.close()
 
-        f = ConIO(2, 'w')
-        self.assertFalse(f.readable())
-        self.assertTrue(f.writable())
-        self.assertEqual(2, f.fileno())
-        f.close()
-        f.close()
+        if sys.stderr.fileno() == 2:
+            f = ConIO(2, 'w')
+            self.assertFalse(f.readable())
+            self.assertTrue(f.writable())
+            self.assertEqual(2, f.fileno())
+            f.close()
+            f.close()
 
     def test_open_name(self):
         f = ConIO("CON")