After hearing today that we using Fizz Buzz in our dev interview process I thought I'd better have a go. Here's my attempt at finding the first 100 Fizz Buzz numbers with tests. So should I get through this stage?

fizzbuzz.rb

class FizzBuzzNumber
  def initialize(value)
    @value = value
  end

  def to_s
    out = []
    out << "fizz" if @value % 3 == 0
    out << "buzz" if @value % 5 == 0
    out.length > 0 ? out.join(" ") : @value.to_s
  end

  def fizz_or_buzz?
    to_s != @value.to_s
  end
end

class TestSuite
  def run
    STDOUT.sync = true
    errors = []
    to_s_cases = [
      [1, "1"],
      [2, "2"],
      [3, "fizz"],
      [4, "4"],
      [5, "buzz"],
      [6, "fizz"],
      [10, "buzz"],
      [15, "fizz buzz"],
    ]

    fizz_or_buzz_cases = [
      [1, false],
      [2, false],
      [3, true],
      [4, false],
      [5, true],
      [5, true],
      [10, true],
      [15, true]
    ]

    run_tests :to_s, to_s_cases, errors
    run_tests :fizz_or_buzz?, fizz_or_buzz_cases, errors

    puts ""
    puts errors.length > 0 ? "#{errors.length} failures" : "Success"
    errors.each do |e| puts e end
  end

  def run_tests(method, cases, errors)
    cases.each do |inputs|
      begin
        run_test method, inputs[0], inputs[1]
        print "."
      rescue => e
        errors << e.message
        print "F"
      end
    end
  end

  def run_test(method, number, expected)
    actual = FizzBuzzNumber.new(number).send(method)
    unless actual == expected
      raise StandardError.new("#{method} for #{number} is #{actual} not #{expected}")
    end
  end

end

TestSuite.new.run

max_items = 100
fizzbuzz_count = 0
counter = 1
output = []

while fizzbuzz_count < max_items do
  number = FizzBuzzNumber.new(counter)
  fizzbuzz_count += 1 if number.fizz_or_buzz?
  output << number
  counter += 1
end

puts output.join(", ")