When NOT to use the Entity Framework

Question

I have been playing around with the EF to see what it can handle. Also many articles and posts explain the various scenarios in which the EF can be used, however if miss the

Answer 1

Since EF does not support POCO, it can be difficult to write good unit tests against. That was one of the knocks against it in the Vote Of No Confidence.

If you're wanting to write good tests, EF will raise obstacles. You can work around them, but it is non-trivial.