Just add the first two

Author: hugovk

Lib/test/test__colorize.py

@@ -51,9 +51,6 @@ def check(env, fallback, expected):
 
             check({'TERM': 'dumb', 'FORCE_COLOR': '1'}, False, True)
             check({'FORCE_COLOR': '1', 'NO_COLOR': '1'}, True, False)
-            check({'FORCE_COLOR': '1', 'NO_COLOR': ''}, True, True)
-            check({'FORCE_COLOR': '', 'NO_COLOR': '1'}, True, False)
-            check({'FORCE_COLOR': '', 'NO_COLOR': ''}, True, True)
 
             for ignore_environment in False, True:
                 # Simulate running with or without `-E`.
@@ -69,9 +66,7 @@ def check(env, fallback, expected):
 
                     check({'TERM': 'dumb', 'PYTHON_COLORS': '1'}, False, not ignore_environment)
                     check({'NO_COLOR': '1', 'PYTHON_COLORS': '1'}, False, not ignore_environment)
-                    check({'NO_COLOR': '', 'PYTHON_COLORS': '1'}, False, not ignore_environment)
                     check({'FORCE_COLOR': '1', 'PYTHON_COLORS': '0'}, True, ignore_environment)
-                    check({'FORCE_COLOR': '', 'PYTHON_COLORS': '0'}, True, ignore_environment)
 
     @unittest.skipUnless(sys.platform == "win32", "requires Windows")
     def test_colorized_detection_checks_on_windows(self):