public void ShouldKnowToInstantiateContext()
{
var dbSet = new Mock<IDbSet<Book>>();
var dbContext = new Mock<PukuDbContext>();
dbContext.Setup(ctx => ctx.GetDbSet<Book>()).Returns(dbSet.Object);
var efRepo = new TestRepository();
Assert.IsNull(efRepo.GetContextInstance());
efRepo.DoStuffThatUsesContextPropery();
Assert.IsNotNull(efRepo.GetContextInstance());
}