tests: Test handling of bad moves in connect four.

This commit tests that we throw a BadMoveException if you
try to move into a "full" column in connect four.  This gets
the controller up to 100% coverage.

zulip_bots/zulip_bots/bots/connect_four/controller.py

@@ -25,6 +25,13 @@ class ConnectFourModel(object):
     def update_board(self, board):
         self.current_board = deepcopy(board)
 
+    def get_column(self, col):
+        # We use this in tests.
+        return [
+            self.current_board[i][col]
+            for i in range(6)
+        ]
+
     def validate_move(self, column_number):
         if column_number < 0 or column_number > 6:
             return False

zulip_bots/zulip_bots/bots/connect_four/test_connect_four.py

@@ -3,6 +3,7 @@ from zulip_bots.test_lib import BotTestCase
 from contextlib import contextmanager
 from unittest.mock import MagicMock
 from zulip_bots.bots.connect_four.connect_four import *
+from zulip_bots.game_handler import BadMoveException
 from typing import Dict, Any, List
 
 
@@ -479,3 +480,24 @@ The first player to get 4 in a row wins!\n Good Luck!')
         confirmWinStates(vertical_win_boards)
         confirmWinStates(major_diagonal_win_boards)
         confirmWinStates(minor_diagonal_win_boards)
+
+    def test_more_logic(self) -> None:
+        model = ConnectFourModel()
+        move = 'move 4'
+        col = 3  # zero-indexed
+
+        self.assertEqual(model.get_column(col), [0, 0, 0, 0, 0, 0])
+        model.make_move(move, player_number=0)
+        self.assertEqual(model.get_column(col), [0, 0, 0, 0, 0, 1])
+        model.make_move(move, player_number=0)
+        self.assertEqual(model.get_column(col), [0, 0, 0, 0, 1, 1])
+        model.make_move(move, player_number=1)
+        self.assertEqual(model.get_column(col), [0, 0, 0, -1, 1, 1])
+        model.make_move(move, player_number=1)
+        self.assertEqual(model.get_column(col), [0, 0, -1, -1, 1, 1])
+        model.make_move(move, player_number=1)
+        self.assertEqual(model.get_column(col), [0, -1, -1, -1, 1, 1])
+        model.make_move(move, player_number=0)
+        self.assertEqual(model.get_column(col), [1, -1, -1, -1, 1, 1])
+        with self.assertRaises(BadMoveException):
+            model.make_move(move, player_number=0)