# 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