fix: extend wait for bucket metadata consistency in system tests (#1053)

* fix: extend wait for bucket metadata consistency in system tests

* delay in bucket access prevention test

---------

Co-authored-by: meredithslota <meredithslota@google.com>

tests/system/_helpers.py

@@ -111,8 +111,12 @@ def delete_bucket(bucket):
     retry(bucket.delete)(force=True)
 
 
-def await_config_changes_propagate(sec=3):
+def await_config_changes_propagate(sec=12):
     # Changes to the bucket will be readable immediately after writing,
     # but configuration changes may take time to propagate.
     # See https://cloud.google.com/storage/docs/json_api/v1/buckets/patch
+    #
+    # The default was changed from 3 to 12 in May 2023 due to changes in bucket
+    # metadata handling. Note that the documentation recommends waiting "30
+    # seconds".
     time.sleep(sec)

tests/system/conftest.py

@@ -44,6 +44,8 @@
     "parent/child/other/file32.txt",
 ]
 
+ebh_bucket_iteration = 0
+
 
 @pytest.fixture(scope="session")
 def storage_client():
@@ -165,12 +167,20 @@ def signing_bucket(storage_client, signing_bucket_name):
     _helpers.delete_bucket(bucket)
 
 
-@pytest.fixture(scope="session")
+@pytest.fixture(scope="function")
 def default_ebh_bucket_name():
-    return _helpers.unique_name("gcp-systest-default-ebh")
+    # Keep track of how many ebh buckets have been created so we can get a
+    # clean one each rerun. "unique_name" is unique per test iteration, not
+    # per test rerun.
+    global ebh_bucket_iteration
+    ebh_bucket_iteration += 1
+    return _helpers.unique_name("gcp-systest-default-ebh") + "-{}".format(
+        ebh_bucket_iteration
+    )
 
 
-@pytest.fixture(scope="session")
+# ebh_bucket/name are not scope=session because the bucket is modified in test.
+@pytest.fixture(scope="function")
 def default_ebh_bucket(storage_client, default_ebh_bucket_name):
     bucket = storage_client.bucket(default_ebh_bucket_name)
     bucket.default_event_based_hold = True

tests/system/test_bucket.py

@@ -920,6 +920,9 @@ def test_new_bucket_created_w_inherited_pap(
 
     bucket.iam_configuration.uniform_bucket_level_access_enabled = False
     bucket.patch()
+
+    _helpers.await_config_changes_propagate()
+
     assert (
         bucket.iam_configuration.public_access_prevention
         == constants.PUBLIC_ACCESS_PREVENTION_ENFORCED