public void Can_Get_TotalTax() { var purchaseOrderSut = new SalesOrder(); purchaseOrderSut.AddOrderLine(new OrderLineStubifier().GivenTax(5m).StubIt()); purchaseOrderSut.AddOrderLine(new OrderLineStubifier().GivenTax(1m).StubIt()); var totalTax = purchaseOrderSut.TotalTax(); Assert.AreEqual(5m + 1m, totalTax); }