codebraker js tdd kata / powered by Jessie / thanks @marcinbunsch!

codebraker.js

var Game = function() {}

Game.prototype.start = function(secret) {
  this.secret = secret;
  return "Hello, Enter guess:";
};

Game.prototype.guess = function(guess) {
  if(guess === this.secret) {
    return "Correct!";
  }

  var guess_arr = String(guess).split('');
  var secret_arr = String(this.secret).split('');
  var answer_arr = [];

  for(var i = 0; i < guess_arr.length; i++) {
    if(guess_arr[i] === secret_arr[i]) {
      answer_arr.push('+');
      delete guess_arr[i];
    }
  }

  for(var i = 0; i < guess_arr.length; i++) {
    for(var j = 0; j < secret_arr.length; j++) {
      if(guess_arr[i] === secret_arr[j]) {
        answer_arr.push('-');
      }
    }
  }

  return answer_arr.join('');
};

exports.Game = Game

game_spec.js

var Game = require('./../lib/codebreaker').Game;

describe('Codebreaker', function() {

  describe('Game', function() {

    var game = new Game();

    describe('#start', function() {
      it("sends a welcome message", function() {
        var message = game.start();
        expect(message).not.toBeUndefined();
        expect(message).toContain('Hello');
      });

      it("prompts for first guess", function() {
        var message = game.start();
        expect(message).not.toBeUndefined();
        expect(message).toContain('Enter guess');
      });

      it("should accept secret code", function() {
        game.start(1234);
        expect(game.secret).not.toBeUndefined();
        expect(game.secret).toEqual(1234);
      });
    });

    describe('#guess', function() {
      beforeEach(function() {
        game.start(1234);
      });

      describe("with a full match", function() {
        it("sends a mark with 'Correct!'", function() {
          var result = game.guess(1234);
          expect(result).toEqual('Correct!');
        });
      });

      describe("with no matches", function() {
        it("sends a mark with ''", function() {
          var result = game.guess(5678);
          expect(result).toEqual('');
        });
      });

      describe("with 1 number match", function() {
        it("sends a mark with '-'", function() {
          var result = game.guess(5618);
          expect(result).toEqual('-');
        });
      });

      describe("with 1 exact match", function() {
        it("sends a mark with '+'", function() {
          var result = game.guess(1678);
          expect(result).toEqual('+');
        });
      });

      describe("with 2 number matches", function() {
        it("sends a mark with '--'", function() {
          var result = game.guess(6512);
          expect(result).toEqual('--');
        });
      });

      describe("with 1 number match and 1 exact match -in that order", function() {
        it("sends a mark with '+-'", function() {
          var result = game.guess(1592);
          expect(result).toEqual('+-');
        });
      });
    });
  });
});