class MockExpectationError < StandardError # :nodoc:
end # omg... worst bug ever. rdoc doesn't allow 1-liners

##
# A simple and clean mock object framework.

module MiniTest

  ##
  # All mock objects are an instance of Mock

  class Mock
    alias :__respond_to? :respond_to?

    skip_methods = %w(object_id respond_to_missing? inspect === to_s)

    instance_methods.each do |m|
      undef_method m unless skip_methods.include?(m.to_s) || m =~ /^__/
    end

    def initialize # :nodoc:
      @expected_calls = {}
      @actual_calls = Hash.new {|h,k| h[k] = [] }
    end

    ##
    # Expect that method +name+ is called, optionally with +args+, and returns
    # +retval+.
    #
    #   @mock.expect(:meaning_of_life, 42)
    #   @mock.meaning_of_life # => 42
    #
    #   @mock.expect(:do_something_with, true, [some_obj, true])
    #   @mock.do_something_with(some_obj, true) # => true
    #
    # +args+ is compared to the expected args using case equality (ie, the
    # '===' operator), allowing for less specific expectations.
    #
    #   @mock.expect(:uses_any_string, true, [String])
    #   @mock.uses_any_string("foo") # => true
    #   @mock.verify  # => true
    #
    #   @mock.expect(:uses_one_string, true, ["foo"]
    #   @mock.uses_one_string("bar") # => true
    #   @mock.verify  # => raises MockExpectationError

    def expect(name, retval, args=[])
      @expected_calls[name] = { :retval => retval, :args => args }
      self
    end

    ##
    # Verify that all methods were called as expected. Raises
    # +MockExpectationError+ if the mock object was not called as
    # expected.

    def verify
      @expected_calls.each_key do |name|
        expected = @expected_calls[name]
        msg1 = "expected #{name}, #{expected.inspect}"
        msg2 = "#{msg1}, got #{@actual_calls[name].inspect}"

        raise MockExpectationError, msg2 if
          @actual_calls.has_key? name and
          not @actual_calls[name].include?(expected)

        raise MockExpectationError, msg1 unless
          @actual_calls.has_key? name and @actual_calls[name].include?(expected)
      end
      true
    end

    def method_missing(sym, *args) # :nodoc:
      expected = @expected_calls[sym]

      unless expected then
        raise NoMethodError, "unmocked method %p, expected one of %p" %
          [sym, @expected_calls.keys.sort_by(&:to_s)]
      end

      expected_args, retval = expected[:args], expected[:retval]

      unless expected_args.size == args.size
        raise ArgumentError, "mocked method %p expects %d arguments, got %d" %
          [sym, expected[:args].size, args.size]
      end

      @actual_calls[sym] << {
        :retval => retval,
        :args => expected_args.zip(args).map { |mod, a| mod === a ? mod : a }
      }

      retval
    end

    def respond_to?(sym) # :nodoc:
      return true if @expected_calls.has_key?(sym.to_sym)
      return __respond_to?(sym)
    end
  end
end