addr0-with-mock.rb

class UnexpectedOutputError < StandardError; end
class MockLogger
  def initialize(expected_indirect_outputs)
    @eio = Array(expected_indirect_outputs)
  end
  def info(s)
    expected = @eio.shift
    if expected != s
      raise UnexpectedOutputError.new("Fail: got #{s}; expected #{expected}")
    end
  end
end

a, b, c, s = examples[0]
expected_logging = <<LOG.split("\n")
augend: 0
addend: 0
carry:  0
sum:    0
LOG
logger = MockLogger.new(expected_logging)                # logger
half_adder = HalfAdder.new(a, b, logger)                 # setup
begin
  half_adder.compute                                     # exercise/verify
  puts "Pass"
rescue UnexpectedOutputError => e
  puts e.messages
end
adder = nil                                              # teardown