Why can't I delete a file in %ProgramFiles% from a Unit Test via Resharper's Test Runner Unit Test?

Question

I am trying to write a test which, in it's fixtures Setup, it backs up a file and deletes the original, runs the test without the original present, then in the teardown, restores the original from the backup. The file is located in my %ProgramFiles% folder. I get an UnauthorizedAccessException on the fileInfo.Delete() statement. I have no problem deleting this file from another test project on the same machine that is not running from the Resharper Test Runner.

I can't move the file to somewhere else - it's ssapi.dll, an installed dll for Visual SourceSafe. (Yes, I'm doing something invasive in a Unit Test.)

It's the same user (me) for both ways -- I checked it via Task Manager. My user account is a member of the local Administrators group. What other factors are there which determine my "Authorization" to do something with a file?

RESOLVED: Though it doesn't answer my original question (which I'd still like to know the answer to), I have found a workaround for my testing purposes, using the System.Security.Permissions framewok, doing a Demand for FileIOPermissionAccess.Read in the app (non-test) code which requires the file (for an Interop call), and a Deny for the same in the test of that code which requires a scenario that that file is not there. This should work for now (and I love having learned a bit about the System.Security.Permissions namespace)!

Answer 1

It is possible that ReSharper is running its Test Runner as a separate process, and that separate process is not using your Windows identity but, instead, another one with lower privileges.

You might be able to verify this opening Task Manager and checking Show processes from all users.

Answer 2

Nope - I see the TaskRunner process in the Task Manager list, but it is under my User Name. But that's what I thought at first, too.

Answer 3

Not really a solution, but I'd consider fixing this problem from a different angle.

You could perhaps consider changing the directory to %AppData% (you might need to make this change for you main application also).

It might solve your problem and also will see you well when you move to Vista, since UAC could stop you (or the application user) from using the %ProgramFiles% directory.

Answer 4

You can probably fix this by giving your user account full access to that folder.

Navigate to the folder in windows explorer. Right click on the folder and select properties. Select the security tab, then the Edit button, and add full control for yourself. Yes - I suppose it's a potential security issue, but you have to change the files in that directory, and you seem to know what you're doing, so it should work.

Answer 5

You could activate auditing for the file, and check the error message in the event log. Note that you have to turn on auditing in two places, once under Local Security Policy/Local Policies/Audit Policy and once on the file itself. This would not solve the problem, but would at least help diagnose the problem.

Answer 6

Are you running Vista or Server 2008 with UAC turned on? If yes, this might be the cause - the test runner process might not be in "elevated" mode.