I used this trick for Integration tests to ensures that each test is ran in a transaction and this transaction is rolled back:

I defined following base class and all my integration test classes can inherit from it.

public abstract class IntegrationTestBase
{
   private TransactionScope scope;

   [TestInitialize]
   public void TestInitialize()
   {
      scope = new TransactionScope();
   }

   [TestCleanup]
   public void TestCleanup()
   {
     scope.Dispose();
   }
}

It works but not for following code:

 [TestMethod]
 public void SaveTwoDocumentsSimultaneously_WorkSuccessfully()
 {
    //Assign

    var doc1 = new Document() { Number = "Test-1" };
    var doc2 = new Document() { Number = "Test-2" };

   //Action
   Parallel.Invoke(() => SaveNewDocument(doc1), () => SaveNewDocument(doc2));
   //Assert
   Assert.IsTrue(true);
}
void SaveNewDocument(Document doc)
{
   using (var ctx = new MyDbContext())
   {
      ctx.Documents.Add(doc);
      ctx.SaveChanges();
   }
}

When the test is passed, there is a record number Test-2 in the database, in other words, the transaction has not been rolled back as I expect(I expect There is no record with numbers Test-1 and Test-2 in the database).

I think I should use DependentTransaction according this link.

How can I use the Transaction that opened in IntegrationTestBase(using TransactionScope) and to use it as parent Transaction?