# File lib/mocha/expectation.rb, line 503
503:     def initialize(mock, expected_method_name, backtrace = nil)
504:       @mock = mock
505:       @method_matcher = MethodMatcher.new(expected_method_name.to_sym)
506:       @parameters_matcher = ParametersMatcher.new
507:       @ordering_constraints = []
508:       @side_effects = []
509:       @cardinality, @invocation_count = Cardinality.exactly(1), 0
510:       @return_values = ReturnValues.new
511:       @yield_parameters = YieldParameters.new
512:       @backtrace = backtrace || caller
513:     end