问题
Can it be done without using TypeMock Islolator? I've found a few suggestions online such as passing in a metadata only connection string, however nothing I've come across besides TypeMock seems to truly allow for a mock ObjectContext that can be injected into services for unit testing. Do I plunk down the $$ for TypeMock, or are there alternatives? Has nobody managed to create anything comparable to TypeMock that is open source?
回答1:
I'm unit testing EF4 easily without mocking. What I did was create a repository interface using the code from http://elegantcode.com/2009/12/15/entity-framework-ef4-generic-repository-and-unit-of-work-prototype/ as a basis I then created an InMemoryRepository<T> class that used the IRepository interface. I then replaced the IObjectSet<T> with a List<T> inside of the class and changed the retrieval methods accordingly.
Thus if you need to do unit testing, pass in the InMemoryRepository rather than the DataRepository.
回答2:
Put your Linq2Entity query behind an interface, unit test it in isolation against a real database.
Write tests for your business logic with mocks for your query interfaces. Don't let Linq bleed into your business logic!
Don't use the RepositoryPattern!
回答3:
Wrap the ObjectContext in a proxy class. Then inject that into your classes.
回答4:
I don't think the repository pattern is the only answer to the question (it avoids the problem, sure)
I liked this answer - I think more appropriate for introducing tests to an existing codebase Creating Interface for ObjectContext
来源：https://stackoverflow.com/questions/2703100/ef4-possible-to-mock-objectcontext-for-unit-testing