def METHOD_NAME(self):
    bp = MessageBreakPlugin()
    n = 1
    action = bp.get_action(self.cframe.ui.tblViewProtocol, self.cframe.protocol_undo_stack,
                           (n, n, 4, 4), self.cframe.proto_analyzer, 0)
    self.assertEqual(self.cframe.protocol_model.row_count, 3)
    original_msg = self.cframe.proto_analyzer.messages[n]
    original_msg.message_type = MessageType("Test", [ProtocolLabel("Test Label", 2, 42, 0)])
    msg_type = original_msg.message_type
    old_msg_len = len(original_msg)
    action.trigger()
    # Now we have two messages: One before and including selection and one behind selection
    msg_1 = self.cframe.proto_analyzer.messages[n]
    msg_2 = self.cframe.proto_analyzer.messages[n + 1]
    self.assertEqual(len(msg_1), 4)
    self.assertEqual(len(msg_2), old_msg_len - 4)
    self.assertEqual(msg_type, msg_1.message_type)
    self.assertEqual(msg_type, msg_2.message_type)
    self.assertEqual(self.cframe.protocol_model.row_count, 4)
    self.cframe.protocol_undo_stack.undo()
    self.assertEqual(self.cframe.protocol_model.row_count, 3)