Add unit test to check invalid ANSI sequences

colorama/ansitowin32.py

@@ -223,16 +223,17 @@ def extract_params(self, command, paramstring):
     def call_win32(self, command, params):
         if command == 'm':
             # Ansi sequences started by specific param may need to be ignored, see #217
-            skip = False
+            skip, skip_count = False, None
             for param in params:
                 if skip:
-                    if skip is not True:
-                        skip -= 1
+                    if skip_count is not None:
+                        skip_count -= 1
                         continue
                     if param in (2, 5):
-                        skip = 1 if param == 5 else 3
+                        skip_count = 1 if param == 5 else 3
                         continue
                     skip = False
+                    skip_count = False
                 if param in self.win32_calls:
                     func_args = self.win32_calls[param]
                     func = func_args[0]

colorama/tests/ansitowin32_test.py

@@ -203,6 +203,22 @@ def testCallWin32UsesLookup(self):
             [a[0][0] for a in listener.call_args_list],
             [33, 11, 22] )
 
+    def testInvalidSequencesAreSkipped(self):
+        sequences = [
+            (38, 5, 46),
+            (38, 2, 120, 33, 255),
+            (48, 5, 31),
+            (48, 2, 166, 226, 46),
+            (38, 48, 5, 46),
+        ]
+        for sequence in sequences:
+            with self.subTest(sequence):
+                listener = Mock()
+                stream = AnsiToWin32(listener)
+                stream.win32_calls = {i: (lambda *_, i=i,**__: listener(i),) for i in [2, 5, 33, 46, 166, 226, 46]}
+                stream.call_win32('m', sequence)
+                self.assertFalse(listener.call_args_list)
+
 
 if __name__ == '__main__':
     main()