These scenarios/tests will run concurrently (well as they are blocked on io), so order of operations might be different than what  you expect. I'd suggest just generating a new ObjectID() for every scenario - that way you start off from a clean slate. 
Example for the delete scenario, specifically create an app before you run the scenario
```
var app_id = ObjectID();
before(function(done) {
   appdao.createApp(app_id, ... , function(err, app) {
       done();
   });
   it('should delete an existing app', function(done) {
       // ... 
   });
```