Quick fix for SHTB (self-hosting test bundle)  server run regression

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | N/A
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

Since the environment refactorings the `server` command doesn't work, this is a very quick fix. The code needs to be refactored/looked-at again. //cc @WouterJ 

One problem is how to choose the test environent when accessing the test server locally @ http://localhost:8000

We do need tests for the Testing bundle, although I'm not sure how this could have been tested.