one transaction for multiple contexts in integration tests on TestInitialize - entity-framework

Question

I am writing integration tests and I want to use transaction scope.
We use EF and Repositories with Contexts.
If I have one Repository and once Context then it would look like this:
[TestInitialize]
public void RuleEngineTestsStart() {
customContext = new CustomContext();
transaction = customContext.Database.BeginTransaction();
repo = new CustomRepository(customContext);
// I need to make this context to work in the same transaction as above
anotherContext = new AnotherContext();
anotherRepo = new AnotherRepository(anotherContext);
}
At the end of tests (TestCleanup) I would like to transaction.Rollback(); everything.
I want to have the same transaction for all repositories that work with different contexts, is it possible? How to create transaction and 'send' it to all three contexts?
Please, to do not to use one Context for all repositories, it is not possible due to reasons (we want to have each context with its own DbSets later to be used within microservices).
Edit
In comments I was asked to include more code, however, I think is not necessary to answer my question.
customContext = new CustomContext();
repo = new CustomRepository(customContext);
customContext2 = new CustomContext2();
otherRepository = new CustomRepository2(customContext2);
// class to be tested needs both repositories
ToBeTestedClass cl = new ToBeTestedClass(customRepository, otherRepository);
// "BASE" interface
public interface IRepository<TEntity> where TEntity : class
{
TEntity GetById(long id);
IEnumerable<TEntity> GetByFilter(Expression<Func<TEntity, bool>> predicate);
TEntity GetSingleByFilter(Expression<Func<TEntity, bool>> filter);
void Insert(TEntity entity);
void Delete(long id);
void Update(TEntity entity);
...
}
// BASE CLASS
public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
{
protected readonly DbContext _context;
protected readonly DbSet<TEntity> _dbSet;
public Repository(ColldeskDbContext context)
{
_context = context;
_dbSet = context.Set<TEntity>();
}
// GetSingle, GetAll, Insert, Update etc.
}
// CustomRepository (other Repositories are similar, with custom methods)
public interface ICustomRepository : IRepository<CusotmData>
{
// some specific methods that are not in Base class
}
public class CustomRepository: Repository<CustomData>, ICustomRepository
{
public CustomRepository(CustomContext context) : base(context)
{
}
// custom methods that are specific for given context
}
// Contexts - each context consists of its one DbSets

Answer 1

Don't use dbContext.SaveChanges() in your repositories. Use ONE dbContext when creating repositories. Sample:
using ( var db = new YourDbContext() )
{
// Create and begin transaction
using ( var transaction = db.Database.BeginTransaction() )
{
try
{
// ONE dbContext for all repositories
var firstRepo = new Custom1Repository(db);
var secondRepo = new Custom2Repository(db);
City city = new City { Description = "My city" };
Street street = new Street { Description = "My street", City = city};
firstRepo.Insert(city);
secondRepo.Insert(street);
// Save all your changes and after that commit transaction
db.SaveChanges();
transaction.Commit();
}
catch ( Exception ec)
{
transaction.Rollback();
}
}
}
Doing like this your repositories becomes just wrappers over DbSet<TEntity>

Answer 2

I have figured out that I can simply use TransactionScope like this:
private TransactionScope _scope;
[TestInitialize]
public void TestInitialize()
{
_scope = new TransactionScope();
}
[TestCleanup]
public void TestCleanup()
{
_scope.Dispose();
}
And then each Context would be running within this TransactionScope.