Yet another "simple" question about unit testing model objects that uses data access layer.
When I mock my Table<Customer>
to IQuerable<ICustomer>
, where new List<FakeCustomer>().AsQuerable()
is used in role of in memory data store, the following code passes unit test perfectly:
var filteredCustomers = from c in dal.Customers
where c.Code.ToUpperInvariant() == "ABC"
select c;
When running app I of cour开发者_开发百科se get NotSupportedException
(because of ToUpperInvariant()
). Maybe it is rather lame example, because problem there can be fixed by replacing ToUpperInvariant()
to ToUpper()
, but you got the point.
Question: is such inconsistency a "fee" for writing real unit but not integration tests? Or maybe I am doing something wrong, e.g. there should be another way to mock DataContext in a way that fully emulates Linq To SQL DataContext?
Currently I am queuing a test database instead of in-memory mock to catch such an errors.
Thanks for your suggestions.
Yes, this is precisely the fee you pay for it not being an integration test. It's a good idea to have integration tests as well as unit tests, of course.
It's hard to avoid this sort of problem with ORMs, in my experience - how are you going to emulate the whole of SQL Server accurately without running SQL Server? That doesn't mean ORMs are useless or anything like that - just that there are limitations.
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