spanner.cloud-client.backup_sample_test: test_list_backup_operations failed

[flaky-bot]

Note: #3239 was also for this test, but it was closed more than 10 days ago. So, I didn't mark it flaky.

---

commit: 79b0d63
buildURL: Build Status, Sponge
status: failed

Test output

Traceback (most recent call last):
  File "/tmpfs/src/github/python-docs-samples/spanner/cloud-client/backup_sample_test.py", line 85, in test_list_backup_operations
    assert BACKUP_ID in out
AssertionError: assert 'test-backup-1uz1u' in ''

[flaky-bot]

Looks like this issue is flaky. 😟

I'm going to leave this open and stop commenting.

A human should fix and close this.

---

When run at the same commit (79b0d63), this test passed in one build (Build Status, Sponge) and failed in another build (Build Status, Sponge).

[tmatsuo]

#3885 picks up the spanner client with longer timeouts. Hopefully this flake will be gone.