[USER STORY] Logic for Hangman game

[jody]

User Story

As a player, I want to play a conventional game of Hangman with the product, so that I can enjoy the word-puzzle-solving experience of a familiar game.

Acceptance Criteria

• The Hangman game allows the player guess a secret word the game has chosen.
• Each player guess may be a single letter or the entire word.
• For each incorrect guess, a part of a hangman figure is drawn (head, body, arms, legs), indicating the number of guesses used up.
• The game ends when the word is correctly guessed (player wins) or the hangman drawing is completed (player loses).

Notes / Design Ideas

Consider the following initial simplifications and extensions:

Words

• Random word chosen from a hardcoded list
  • (Extension) Hardcoded list replaced by loading word list from a file
• Only alphabetic characters
• Case-insensitive

Gameplay

• 6 incorrect guesses (tries) allowed
  • (Extension) Parameterized with customization of hangman diagram
• User can guess a letter or a full word
• Incorrect full word guesses cost one try
• Repeated guesses are not penalized

User Interface

• Command-Line Interface (scanner-based OK)
• Current word progress is shown using dashes for not-yet-guessed letters (initially all dashes)
• After each guess:
  • ASCII hangman diagram is shown
  • Letters already guessed are shown
  • Current word progress is shown

Scoring

• If the player wins, the score equals the number of remaining tries
• If the player loses, the score is zero (0)
• play() returns Optional.of(score)

Testability

Consider providing for injection of an InputStream to facilitate testing. For example, include a no-parameter constructor public HangmanGame() that invokes a parameterized constructor public HangmanGame(InputSream)

Consider adding testing helper methods that are either protected or package-private. For example,

• a method that returns the set of guessed letters (such as by a Set<Character>))
• a method that returns the current number of remaining tries (an int)
• a method that returns whether or not the word is fully guessed (a boolean)
• a method that sets the secret word

Some examples of test methods:

• Simulate winning a game where the user guesses letters and wins.
• Simulate a winning game by a full word guess.
• Simulate a losing game after 6 incorrect guesses.
• Simulate repeated letter guesses to ensure they don't reduce remaining tries
• Simulate invalid input (non-alphabetic) and ensure it is igrnored