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Python Python Testing First Steps With Testing Writing and Running Doctests

Henry Lin
Henry Lin
11,636 Points
Posted by Henry Lin
Henry Lin
11,636 Points

Does anyone know how to write doctest for move_player()?

""" >>> cells = build_cells(3, 3) >>> move_player((1,1), 'RIGHT') (2, 1)

"""

Here is mine but it gave me this:

File "/home/treehouse/workspace/dungeon/dd_game.py", line 83, in dd_game.move_player
Failed example:
move_player((1,1), 'DOWN')
Exception raised:
Traceback (most recent call last):
File "/usr/local/pyenv/versions/3.5.0/lib/python3.5/doctest.py", line 1320, in __run
compileflags, 1), test.globs)
File "<doctest dd_game.move_player[1]>", line 1, in <module>
move_player((1,1), 'DOWN')
File "/home/treehouse/workspace/dungeon/dd_game.py", line 87, in move_player
x, y = player['location']
TypeError: tuple indices must be integers or slices, not str

1 Answer

Casey Nord
Casey Nord
12,141 Points
Casey Nord
Casey Nord
12,141 Points

This one confused me for a bit too. What seems to be an obvious answer (and is if we are using the version of this game written in the Python Collections course), turns out to have a few more pieces to it.

If we look back near the beginning of dd_game.py we can see that the variable player is set up like this:

player = {'location': None, 'path': []}

This is how we need to format player when we pass it to the move_player function for testing:

def move_player(player, move):
    """Move player one space in indicated direction

    >>> move_player({'location': (1, 1), 'path': []}, 'LEFT')
    (0, 1)

    """
    x, y = player['location']
    player['path'].append((x, y))
    if move == 'LEFT':
        x -= 1
    elif move == 'UP':
        y -= 1
    elif move == 'RIGHT':
        x += 1
    elif move == 'DOWN':
        y += 1
    return x, y

I'm still just starting to gain some momentum with Python, but what I think is happening is that the function loses itself when it tries to unpack player from the dict ['location'], and again when trying to append to ['path'], resulting in the somewhat confusing TypeError.