Fix a bug in mongoreader preventing using existing collections (#167)

Fix a bug in mongoreader preventing using existing collections (it didnt like being being cast to a boolean)

locust_plugins/mongoreader.py

@@ -34,9 +34,12 @@ def __init__(
 
         """
         self.timestamp_field = timestamp_field
-        self.coll: Collection = (
-            coll or MongoClient(env["LOCUST_MONGO"])[env["LOCUST_MONGO_DATABASE"]][env["LOCUST_MONGO_COLLECTION"]]
-        )
+        if not coll:
+            self.coll: Collection = MongoClient(env["LOCUST_MONGO"])[env["LOCUST_MONGO_DATABASE"]][
+                env["LOCUST_MONGO_COLLECTION"]
+            ]
+        else:
+            self.coll = coll
         self.cursor: Cursor = self.coll.find(filter, sort=[(self.timestamp_field, 1)])
         records_in_buffer = self.cursor._refresh()  # trigger fetch immediately instead of waiting for the first next()
         if not records_in_buffer:

test/test_cloudwatch_plugin.py

@@ -10,19 +10,20 @@
 
 setup_logging("INFO", None)
 
+
 class CloudwatchMock:
     def __init__(self):
         self.call_count = 0
         self.metrics_dict = {}
 
-
     def put_metric_data(self, Namespace, MetricData):
         self.call_count += 1
         self.metrics_dict[Namespace] = MetricData
 
 
 cw = CloudwatchMock()
 
+
 def on_locust_init(environment, **_kwargs):
     CloudwatchAdapter(environment, "MyExampleService", "perf", cw)