public void In_memory_DbSet_can_be_used_for_Add()
        {
            var set     = new InMemoryNonGenericDbSet <Product>();
            var product = new Product();

            Assert.Same(product, set.Add(product));
            Assert.Same(product, set.ToList <Product>().Single());
        }
        public void In_memory_DbSet_can_be_used_for_Remove()
        {
            var set     = new InMemoryNonGenericDbSet <Product>();
            var product = new Product();

            set.Add(product);

            Assert.Same(product, set.Remove(product));
            Assert.Empty(set);
        }