Allow better parallelization in firestore tests

Author: TimPansino

tests/datastore_firestore/test_client.py

@@ -32,7 +32,7 @@ def existing_document(collection, reset_firestore):
 
 
 def _exercise_client(client, collection, existing_document):
-    assert len([_ for _ in client.collections()]) == 1
+    assert len([_ for _ in client.collections()]) >= 1
     doc = [_ for _ in client.get_all([existing_document])][0]
     assert doc.to_dict()["x"] == 1