Unit Test with transaction: CREATE DATABASE statement not allowed within multi-statement transaction - entity-framework

Question

I have base class for my unit tests:
public abstract class DatabaseTestsBase
{
protected OvuContext DbContext;
protected TransactionScope TransactionScope;
[SetUp]
public void TestSetup()
{
TransactionScope = new TransactionScope(TransactionScopeOption.RequiresNew);
DbContext = new OvuContext("IntegrationTestContext");
}
[TearDown]
public void TestCleanup()
{
TransactionScope.Dispose();
}
}
And the test itself:
[TestFixture]
public class MyEntityTests : DatabaseTestsBase
{
[Test]
public void MyEntity_Create_HasSucceeded()
{
var myEntity = new MyEntity(Guid.NewGuid());
myEntity.Description = "bla bla bla";
var id = myEntity.Id;
DbContext.MyEntities.Add(myEntity);
DbContext.SaveChanges();
var temp = DbContext.MyEntities.Single(x => x.Id == id);
ComparisonResult result = CompareLogic.Compare(myEntity, temp);
Assert.True(result.AreEqual);
}
}
I got the following error when the test runs:
CREATE DATABASE statement not allowed within multi-statement transaction
The 'strange' thing is that when I run the test a second time, it passes.

Answer 1

I believe you are taking the pattern of rolling back database side-effecting Integration / Unit Tests done under an uncommitted transaction (such as TransactionScope) a bit far :)
Code First EF is attempting to create the database under the context of the ambient TransactionScope, which isn't possible.
In Sql Server (and possibly other RDBMS's), it isn't possible to execute certain statements, such as CREATE DATABASE, command under a transaction. You'll get the same error if you execute the following directly in SSMS:
use master;
BEGIN TRAN
CREATE DATABASE FOO;
-- CREATE DATABASE statement not allowed within multi-statement transaction.
I would suggest that you change your strategy such that you pre-create a permanent, empty test database for testing. Other DDL statements executed by EF Code First, such as CREATE TABLE can be rolled back by the uncommitted TransactionScope.