Merge pull request #2748 from graingert-coef/prevent-celery-tests-hanging-if-celery-fails-to-start

prevent celery tests hanging if celery fails to start

Author: alexcjohnson

tests/integration/long_callback/utils.py

@@ -94,14 +94,19 @@ def setup_long_callback_app(manager_name, app_name):
                 "2",
                 "--loglevel=info",
             ],
+            encoding="utf8",
             preexec_fn=os.setpgrp,
             stderr=subprocess.PIPE,
         )
         # Wait for the worker to be ready, if you cancel before it is ready, the job
         # will still be queued.
+        lines = []
         for line in iter(worker.stderr.readline, ""):
-            if "ready" in line.decode():
+            if "ready" in line:
                 break
+            lines.append(line)
+        else:
+            raise RuntimeError("celery failed to start: " + {"\n".join(lines)})
 
         try:
             yield import_app(f"tests.integration.long_callback.{app_name}")