Hangman Game

This project is part of our Data Science and Web Development courses.

For today's project, we'll be rewriting our previous Hangman Game using OOP. We'll explore fundamental object oriented design concepts.

There will be three main classes:

• HangmanGame: the main interface for the user, the "general" game that will be used.
• GuessWord: A word to guess. Is used by a HangmanGame to keep track of the word to guess.
• GuessAttempt: An attempt to guess a letter.

Each one of these classes have its own test file where you can see in more detail their interfaces.

Before exploring each class in detail, let us show you a general Hangman match with the new OOP interface:

game = HangmanGame(['abc'], number_of_guesses=5)

attempt = game.guess('a')
assert attempt.is_hit() is True
assert game.remaining_misses == 5
assert game.previous_guesses == ['a']
assert game.word.masked == 'a**'

attempt = game.guess('x')  # Miss!
assert attempt.is_miss() is True
assert game.remaining_misses == 4
assert game.previous_guesses == ['a', 'x']
assert game.word.masked == 'a**'

attempt = game.guess('c')
assert attempt.is_hit() is True
assert game.remaining_misses == 4
assert game.previous_guesses == ['a', 'x', 'c']
assert game.word.masked == 'a*c'

attempt = game.guess('z')  # Miss!
assert attempt.is_miss() is True
assert game.remaining_misses == 3
assert game.previous_guesses == ['a', 'x', 'c', 'z']
assert game.word.masked == 'a*c'

game.guess('b')  # Raises GameWonException!

# After the exception:
assert game.is_finished() is True
assert game.is_won() is True
assert game.is_lost() is False

assert game.remaining_misses == 3
assert game.previous_guesses == ['a', 'x', 'c', 'z', 'b']
assert game.word.masked == 'abc'

HangmanGame class

$ py.test test_hangman_game.py

This is the main Game class that will keep control of the overall "game status". It'll receive guess attempts (game.guess), will check for general business logic/rules (if the game is not already finished, if there are remaining attempts available in this match, if the character wasn't used before, etc) and if everything goes well it'll just rely on the GuessWord class to "perform an attempt" (guess_word.perform_attempt).

The HangmanGame class has one classmethod select_random_word that receives a list of words and selects one randomly.

A HangmanGame is constructed by optionally passing a list of words and the number of attempts: HangmanGame(word_list=['Python', 'rmotr'], number_of_guesses=3). But these parameters are optional, if not provided:

• the number_of_guesses should be 5
• the word_list should be taken from the class variable HangmanGame.WORD_LIST that should be equals to ['rmotr', 'python', 'awesome']

print(HangmanGame.WORD_LIST)  # ['rmotr', 'python', 'awesome']

GuessWord class

$ py.test test_guess_word.py

GuessWord keeps track of the word to guess and the current state of the "masked" word. It is constructed by passing a word to guess (GuessWord('xyz')) and it has a public perform_attempt method that takes one character and returns a GuessAttempt (more details below). Here's its simple interface:

word = GuessWord('xyz')
assert word.answer == 'xyz'
assert word.masked == '***'

attempt = word.perform_attempt('x')  # Hit!
assert word.masked == 'x**'

attempt = word.perform_attempt('a')  # Miss!
assert word.masked == 'x**'

attempt = word.perform_attempt('abc')  # Invalid! Should raise InvalidGuessedLetterException.
assert word.masked == 'x**'

GuessAttempt class

$ py.test test_guess_attempt.py

GuessAttempt objects are returned when an attempt is performed on a GuessWord object, they shouldn't be constructed manually outside of the GuessWord.perform_attempt method. A GuessAttempt has two methods is_hit() and is_miss() depending on the result of the attempt:

word = GuessWord('xyz')

attempt = word.perform_attempt('x')  # Hit!
assert attempt.is_hit() is True
assert attempt.is_miss() is False

attempt = word.perform_attempt('a')  # Miss!
assert attempt.is_miss() is True
assert attempt.is_hit() is False

Play the game!

As usual, you can use the main.py script to play the game once it's resolved.

Complete Walkthrough solution