# File lib/mocha/mock.rb, line 41
41:     def expects(method_name_or_hash, backtrace = nil)
42:       iterator = ArgumentIterator.new(method_name_or_hash)
43:       iterator.each { |*args|
44:         method_name = args.shift
45:         ensure_method_not_already_defined(method_name)
46:         expectation = Expectation.new(self, method_name, backtrace)
47:         expectation.returns(args.shift) if args.length > 0
48:         @expectations.add(expectation)
49:       }
50:     end