public void TestPrice() { _repository = Substitute.For <IInstrumentRepository>(); _repository.GetInstruments() .Returns(new List <Instrument> { new Instrument("Toto", InstrumentType.Bond) }); _pricer = new Pricer(_repository, 500); _pricer.Price(); Thread.Sleep(800); _repository.Received(1).PriceUpdate("Toto", Arg.Any <double>()); }