[storage] fix: use a different bucket for requester_pays_test

fixes #3654

storage/cloud-client/README_TEST.md

@@ -0,0 +1,16 @@
+
+For requester_pays_test.py, we need to use a different Storage bucket.
+
+The test looks for an environment variable
+`REQUESTER_PAYS_TEST_BUCKET` first and then fallback to
+`${CLOUD_STORAGE_BUCKET} + '-requester-pays-test'`.
+
+On the test project, we created a bucket named
+`python-docs-samples-tests-requester-pays-test`.
+
+
+Also, the service account for the test needs to have `Billing Project
+Manager` role in order to make changes on buckets with requester pays
+enabled.
+
+We added that role to the test service account.

storage/cloud-client/requester_pays_test.py

@@ -23,7 +23,14 @@
 import storage_download_file_requester_pays
 import storage_get_requester_pays_status
 
-BUCKET = os.environ["CLOUD_STORAGE_BUCKET"]
+
+# We should not use the same bucket as other tests are using.
+# First look at REQUESTER_PAYS_TEST_BUCKET and fall back to
+# ${CLOUD_STORAGE_BUCKET} + '-requester-pays-test'.
+BUCKET = os.environ.get(
+    "REQUESTER_PAYS_TEST_BUCKET",
+    "{}-requester-pays-test".format(os.environ["CLOUD_STORAGE_BUCKET"])
+)
 PROJECT = os.environ["GCLOUD_PROJECT"]