private void TestRemoveThenAddGraphDiscarded(IStorageProvider manager)
        {
            this.EnsureTestDataset(manager);

            PersistentTripleStore store = new PersistentTripleStore(manager);

            try
            {
                Uri    toRemove = new Uri(TestGraphUri1);
                IGraph g        = store[toRemove];
                Assert.True(store.HasGraph(toRemove), "In-memory view should contain the Graph we wish to remove");

                store.Remove(toRemove);
                Assert.False(store.HasGraph(toRemove), "In-memory view should no longer contain the Graph we removed prior to the Flush/Discard operation");

                store.Add(g);
                Assert.True(store.HasGraph(toRemove), "In-memory should now contain the Graph we added back");

                store.Discard();

                Assert.True(store.HasGraph(toRemove), "In-Memory view should still contain the Graph we removed and added back regardless as we Discarded that change");
                AnyHandler handler = new AnyHandler();
                manager.LoadGraph(handler, toRemove);
                Assert.True(handler.Any, "Attempting to load Graph from underlying store should return something as the Discard() prevented the removal and add back being persisted");
            }
            finally
            {
                store.Dispose();
            }
        }
        private void TestAddThenRemoveGraphDiscarded(IStorageProvider manager)
        {
            this.EnsureTestDataset(manager);

            PersistentTripleStore store = new PersistentTripleStore(manager);

            try
            {
                Graph g = new Graph();
                g.BaseUri = new Uri("http://example.org/persistence/graphs/added/discarded");
                this.EnsureGraphDeleted(manager, g.BaseUri);
                g.Assert(g.CreateUriNode("rdf:subject"), g.CreateUriNode("rdf:predicate"), g.CreateUriNode("rdf:object"));
                store.Add(g);

                Assert.True(store.HasGraph(g.BaseUri), "Newly added graph should exist in in-memory view of store");
                Assert.False(manager.ListGraphs().Contains(g.BaseUri), "Newly added graph should not yet exist in underlying store");

                store.Remove(g.BaseUri);
                Assert.False(store.HasGraph(g.BaseUri), "Graph then removed before Flush/Discard() should no longer exist in in-memory view of store");
                Assert.False(manager.ListGraphs().Contains(g.BaseUri), "Graph then removed should still not exist in underlying store");

                store.Discard();

                Assert.False(store.HasGraph(g.BaseUri), "After Discard() is called graph should not exist in in-memory view of store");
                Assert.False(manager.ListGraphs().Contains(g.BaseUri), "After Discard() is called added then removed graph should not exist in underlying store");
            }
            finally
            {
                store.Dispose();
            }
        }
        private void TestRemoveThenAddGraphFlushed(IStorageProvider manager)
        {
            this.EnsureTestDataset(manager);

            PersistentTripleStore store = new PersistentTripleStore(manager);

            try
            {
                Uri    toRemove = new Uri(TestGraphUri1);
                IGraph g        = store[toRemove];
                Assert.True(store.HasGraph(toRemove), "In-memory view should contain the Graph we wish to remove");

                store.Remove(toRemove);
                Assert.False(store.HasGraph(toRemove), "In-memory view should no longer contain the Graph we removed prior to the Flush/Discard operation");

                store.Add(g);
                Assert.True(store.HasGraph(toRemove), "In-memory should now contain the Graph we added back");

                store.Flush();

                Assert.True(store.HasGraph(toRemove), "In-Memory view should still contain the Graph we added back after Flushing");
                AnyHandler handler = new AnyHandler();
                manager.LoadGraph(handler, toRemove);
                Assert.True(handler.Any, "Attempting to load Graph from underlying store should return something after the Flush() operation since we didn't remove the graph in the end");
            }
            finally
            {
                store.Dispose();
            }
        }
        private void TestAddGraphDiscarded(IStorageProvider manager)
        {
            this.EnsureTestDataset(manager);

            PersistentTripleStore store = new PersistentTripleStore(manager);

            try
            {
                Graph g = new Graph();
                g.BaseUri = new Uri("http://example.org/persistence/graphs/added/discarded");
                this.EnsureGraphDeleted(manager, g.BaseUri);
                g.Assert(g.CreateUriNode("rdf:subject"), g.CreateUriNode("rdf:predicate"), g.CreateUriNode("rdf:object"));
                store.Add(g);

                Assert.True(store.HasGraph(g.BaseUri), "Newly added graph should exist in in-memory view of store");
                Assert.False(manager.ListGraphs().Contains(g.BaseUri), "Newly added graph should not yet exist in underlying store");

                store.Discard();

                Graph h = new Graph();
                try
                {
                    manager.LoadGraph(h, g.BaseUri);
                }
                catch
                {
                    //No catch needed
                }
                Assert.True(h.IsEmpty, "After Discard() is called a graph may exist in the underlying store but it MUST be empty");
            }
            finally
            {
                store.Dispose();
            }
        }