fix(monitoring): retry in the test setup (#4702)

fixes #4687
fixes #4688
fixes #4689
fixes #4690

Author: Takashi Matsuo

monitoring/api/v3/cloud-client/snippets_test.py

@@ -16,6 +16,7 @@
 import re
 
 import backoff
+from google.api_core.exceptions import InternalServerError
 from google.api_core.exceptions import NotFound
 import pytest
 
@@ -42,7 +43,12 @@ def custom_metric_descriptor(capsys):
 
 @pytest.fixture(scope="module")
 def write_time_series():
-    snippets.write_time_series(PROJECT_ID)
+
+    @backoff.on_exception(backoff.expo, InternalServerError, max_time=120)
+    def write():
+        snippets.write_time_series(PROJECT_ID)
+
+    write()
     yield