I have a simple Entity Framework 4 unit test that creates a new record, saves it, attempts to find it, then deletes it. All works great, unless...
... I open up SQL Server Management Studio while stopped at a breakpoint in the unit test and execute a SELECT statement that returns the row I just created (not SELECT FOR UPDATE, not WITH (updlock), no transaction, just a plain SELECT).
If I do that before attempting to find the row I just created, I don't find the row. If I instead do that after finding the row but before deleting the row, I do find the row but get an OptimisticConcurrencyException.
This is consistently repeatable.
Unit Test:
[TestMethod()]
public void CreateFindDeleteActiveParticipantsTest()
{
// Setup this test
Participant utPart = CreateUTParticipant();
ctx.Participants.AddObject(utPart);
ctx.SaveChanges();
// External SELECT Point #1:
// part is null
// Find participant
Participant part = ParticipantRepository.Find(UT_SURVEY_ID, UT_TOKEN);
Assert.IsNotNull(part, "Expected to find a participant");
// External SELECT Point #2:
// SaveChanges throws OptimisticConcurrencyException
// Cleanup this test
ctx.Participants.DeleteObject(utPart);
ctx.SaveChanges();
}
