expects (Mocha::Mock)

        # File lib/mocha/mock.rb, line 42
    42:     def expects(method_name_or_hash, backtrace = nil)
    43:       iterator = ArgumentIterator.new(method_name_or_hash)
    44:       iterator.each { |*args|
    45:         method_name = args.shift
    46:         ensure_method_not_already_defined(method_name)
    47:         expectation = Expectation.new(self, method_name, backtrace)
    48:         expectation.returns(args.shift) if args.length > 0
    49:         @expectations.add(expectation)
    50:       }
    51:     end