The call to _setCommand_ ends the nimble run, that's why the second file was
not processed. One possible solution: make testing a file a task of its own
named e.g. _testFile_ and call it as often as needed from another task like
this:
exec "nimble testFile <whatever call parameters are needed>"
Inside _testFile_, the call parameters can be read with _paramStr(i)_. Not the most elegant way perhaps, but it works. Maybe _selfExec_ would be better, but that crashed on me IIRC.
