Cloud9 Ruby Project

Specs: spec/rock_paper_scissors_spec.rb

In a game of rock-paper-scissors, each player chooses to play Rock (R), Paper (P), or Scissors (S). The rules are: Rock breaks Scissors, Scissors cuts Paper, but Paper covers Rock. (In other words, Rock wins over Scissors, Scissors wins over Paper, and Paper wins over Rock.)

In a round of rock-paper-scissors, each player's name and strategy is encoded as an array of two elements

[ ["Kristen", "P"], ["Jacob", "S"] ] # Jacob would win since S > P

A: Game Winner:

Create a RockPaperScissors class with a class method winner that takes two 2-element arrays like those above, and returns the one representing the winner:

RockPaperScissors.winner(['Kristen,'P'], ['Jacob','S']) # => ['Jacob','S']

If either player's strategy is something other than "R", "P" or "S" (case-insensitive), the method should raise a RockPaperScissors::NoSuchStrategyError exception.

If both players use the same strategy, the first player is the winner.

B: Tournament:

A rock-paper-scissors tournament is encoded as an array of games - that is, each element can be considered its own tournament.

[ [ [ ["Kristen", "P"], ["Ben", "S"] ], [ ["Justin", "R"], ["Walter", "S"] ], ], [ [ ["Allen", "S"], ["Omer", "P"] ], [ ["David", "R"], ["Richard", "P"] ] ] ]

In the tournament above Kristen will always play P and Ben will always play S. This tournament plays out as follows:

Under this scenario, Ben would beat Kristen (S>P) and Justin would beat Walter (R>S), so Ben and Justin would play (Justin wins since R>S); similarly, Allen would beat Omer, Richard would beat David, and Allen and Richard would play (Allen wins since S>P); and finally Justin would beat Allen since R>S. That is, pairwise play continues until there is only a single winner.

Write a method `RockPaperScissors.tournament_winner' that takes a tournament encoded as an array and returns the winner (for the above example, it should return ['Justin', 'R']). You can assume that the array is well formed (that is, there are 2n players, and each one participates in exactly one match per round).

HINT: Formulate the problem as a recursive one whose base case you solved in part A.

Select one of the rspec tests, copy it, and modify it so that it tests a feature of the rock-paper-scissors library you have implemented. Alternatively, you can write your own test.

Finally, go to your text file and summarize the purpose of each rspec test (including your added test).

1 class RockPaperScissors 3 4 # Exceptions this class can raise: 4 class NoSuchStrategyError