The test 'should return correct result even for objects as arguments' doesn't work properly. This description confused me.

param1 = {foo: 'foo', bar: 'bar'};
param2 = {bar: 'bar', foo: 'foo'};

Object like param1 and param2 should be cashed like identical parameters because they have the same keys and values. But the test counts these objects like differnt parameters.