RavenDB Unit Test - Saving changes to document should not alter doc id casing

CasingTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Raven.Client;
using Raven.Client.Embedded;
using Xunit;
using System.Text.RegularExpressions;

namespace RavenCasingTest
{
	public class CasingTest
	{
		[Fact]
		public void Saving_changes_to_document_should_not_alter_doc_id_casing()
		{
			using (IDocumentStore store = new EmbeddableDocumentStore { RunInMemory = true })
			{
				store.Initialize();

				TestModel tm1 = new TestModel
				{
					Name = "Test #1"
				};

				Assert.Null(tm1.Id);

				using (IDocumentSession session = store.OpenSession())
				{
					session.Store(tm1);
					AssertCasing(tm1.Id, "After initial store, DocId should be mixed case due to conventions.");
					session.SaveChanges();
				}
				AssertCasing(tm1.Id, "DocId should be unchnaged after SaveChanges is called.");

				string lastPart = tm1.Id.Split('/')[1];

				Assert.True(Regex.IsMatch(lastPart, @"^\d+$"), "The segment of the Id after the slash should match an integer pattern.");

				int intId = int.Parse(lastPart);

				using (IDocumentSession session = store.OpenSession())
				{
					var tm2 = session.Load<TestModel>(intId);
					AssertCasing(tm2.Id, "After loading the doc from store, the casing should still be mixed.");
					tm2.DeletedUtc = DateTime.UtcNow;
					AssertCasing(tm2.Id, "Setting the DeletedUtc property should have no effect on the casing.");
					session.SaveChanges();
					AssertCasing(tm2.Id, "Saving changes on the Set DeletedUtc operation should have no effect on the casing.");
				}

				using (IDocumentSession session = store.OpenSession())
				{
					var tm3 = session.Load<TestModel>(intId);
					AssertCasing(tm3.Id, "When reloading doc after updating the DeletedUtc property, the casing should still be mixed.");
				}
			}
		}

		private void AssertCasing(string docId, string errorMsg)
		{
			Assert.True(docId != null && docId.StartsWith("TestModels/", StringComparison.InvariantCulture), errorMsg);
		}

		public class TestModel
		{
			public string Id { get; set; }
			public string Name { get; set; }
			public DateTime DeletedUtc { get; set; }
		}
	}
}