public void Contains()
        {
            var collection = new InstanceCollectionInt32 <Instance>();
            var instance   = new Instance();
            int id         = collection.Add(instance);

            Assert.IsTrue(collection.Contains(id), "collection.Contains(id)");

            collection.Remove(id);

            Assert.IsFalse(collection.Contains(id), "collection.Contains(id)");
        }
        public void Add()
        {
            var collection = new InstanceCollectionInt32 <Instance>();
            var instance   = new Instance();
            int id         = collection.Add(instance);

            Assert.AreEqual(id, collection.Generator.PreviousIdentifier);
            Assert.IsTrue(collection.Contains(id), "collection.Contains(id)");
            Assert.IsTrue(collection.Generator.IsValid(id), "collection.Generator.IsValid(id)");
        }