Enable debug logging in flamenco_worker.commands while testing commands

tests/test_runner.py

 import asyncio
+import logging
 from unittest.mock import Mock, call
 
 from tests.abstract_worker_test import AbstractWorkerTest
@@ -18,6 +19,8 @@ class AbstractCommandTest(AbstractWorkerTest):
         self.fworker.register_log = CoroMock()
         self.fworker.register_task_update = CoroMock()
 
+        logging.getLogger('flamenco_worker.commands').setLevel(logging.DEBUG)
+
     def tearDown(self):
         # This is required for subprocesses, otherwise unregistering signal handlers goes wrong.
         self.loop.close()