class RSpec::Matchers::BuiltIn::RespondTo

def argument
  self
end

def description
  "respond to #{pp_names}#{with_arity}"
end

def does_not_match?(actual)
  find_failing_method_names(actual, :select).empty?
end

def failure_message_for_should
  "expected #{@actual.inspect} to respond to #{@failing_method_names.collect {|name| name.inspect }.join(', ')}#{with_arity}"
end

def failure_message_for_should_not
  failure_message_for_should.sub(/to respond to/, 'not to respond to')
end

def find_failing_method_names(actual, filter_method)
  @actual = actual
  @failing_method_names = @names.__send__(filter_method) do |name|
    @actual.respond_to?(name) && matches_arity?(actual, name)
  end
end

def initialize(*names)
  @names = names
  @expected_arity = nil
end

def matches?(actual)
  find_failing_method_names(actual, :reject).empty?
end

def matches_arity?(actual, name)
  return true unless @expected_arity
  actual_arity = actual.method(name).arity
  if actual_arity < 0
    # ~ inverts the one's complement and gives us the number of required args
    ~actual_arity <= @expected_arity
  else
    actual_arity == @expected_arity
  end
end

def pp_names
  # Ruby 1.9 returns the same thing for array.to_s as array.inspect, so just use array.inspect here
  @names.length == 1 ? "##{@names.first}" : @names.inspect
end

def supports_block_expectations?
  false
end

def with(n)
  @expected_arity = n
  self
end

def with_arity
  @expected_arity.nil?? "" :
    " with #{@expected_arity} argument#{@expected_arity == 1 ? '' : 's'}"
end