Fixing the secret key, and url to be visited.

I noticed `$processedUri` ends up looking like `/[adminRouter]/[controller]/[action]/key/[key]/[action]`

I also noticed, when the key is generated, it is generated using just the admin router. Which is incorrect, it should be generated using either just the controller, or the controller and action.

Finally, when `$this->getSession()->visit($processedUri)` is run, for me, the url generated looked like: `http://localhost/admin/[controller]/[action]/key/[key]/[action]/`. The expected result was: `http://mymachine.local/myproject/admin/[controller]/[action]/key/[key]/`. Passing `$processedUri` through `$this->locatePath()` fixed the issue.