# File lib/mocha/expectation.rb, line 501
    def initialize(mock, expected_method_name, backtrace = nil)
      @mock = mock
      @method_matcher = MethodMatcher.new(expected_method_name.to_sym)
      @parameters_matcher = ParametersMatcher.new
      @ordering_constraints = []
      @side_effects = []
      @cardinality = Cardinality.exactly(1)
      @invocation_count = 0
      @return_values = ReturnValues.new
      @yield_parameters = YieldParameters.new
      @backtrace = backtrace || caller
    end