test_worker: fix asyncio event loop management

artiq/test/test_worker.py

@@ -62,44 +62,42 @@ async def _call_worker(worker, expid):
         await worker.close()
 
 
-def _run_experiment(class_name):
-    expid = {
-        "log_level": logging.WARNING,
-        "file": sys.modules[__name__].__file__,
-        "class_name": class_name,
-        "arguments": dict()
-    }
-    loop = asyncio.get_event_loop()
-    worker = Worker({})
-    loop.run_until_complete(_call_worker(worker, expid))
-
-
 class WorkerCase(unittest.TestCase):
     def setUp(self):
         self.loop = asyncio.new_event_loop()
         asyncio.set_event_loop(self.loop)
 
+    def _run_experiment(self, class_name):
+        expid = {
+            "log_level": logging.WARNING,
+            "file": sys.modules[__name__].__file__,
+            "class_name": class_name,
+            "arguments": dict()
+        }
+        worker = Worker({})
+        self.loop.run_until_complete(_call_worker(worker, expid))
+
     def test_simple_run(self):
-        _run_experiment("SimpleExperiment")
+        self._run_experiment("SimpleExperiment")
 
     def test_exception(self):
         with self.assertLogs() as logs:
             with self.assertRaises(WorkerInternalException):
-                _run_experiment("ExceptionTermination")
+                self._run_experiment("ExceptionTermination")
             self.assertGreater(len(logs.records), 0)
             self.assertIn("Terminating with exception (TypeError)",
                           logs.output[-1])
 
     def test_watchdog_no_timeout(self):
-        _run_experiment("WatchdogNoTimeout")
+        self._run_experiment("WatchdogNoTimeout")
 
     def test_watchdog_timeout(self):
         with self.assertRaises(WorkerWatchdogTimeout):
-            _run_experiment("WatchdogTimeout")
+            self._run_experiment("WatchdogTimeout")
 
     def test_watchdog_timeout_in_build(self):
         with self.assertRaises(WorkerWatchdogTimeout):
-            _run_experiment("WatchdogTimeoutInBuild")
+            self._run_experiment("WatchdogTimeoutInBuild")
 
     def tearDown(self):
         self.loop.close()