Print hub logs if hubtraf fails in integration tests

integration-tests/test_hub.py

@@ -132,6 +132,7 @@ async def test_long_username():
     # FIXME: wait for reload to finish & hub to come up
     # Should be part of tljh-config reload
     await asyncio.sleep(1)
+    try:
         async with User(username, hub_url, partial(login_dummy, password='')) as u:
                 await u.login()
                 await u.ensure_server()
@@ -141,3 +142,11 @@ async def test_long_username():
                 assert pwd.getpwnam(system_username) is not None
 
                 await u.stop_server()
+    except:
+        # If we have any errors, print jupyterhub logs before exiting
+        subprocess.check_call([
+            'journalctl',
+            '-u', 'jupyterhub',
+            '--no-pager'
+        ])
+        raise