tests: harden old instance cleanup against NotFound (#471)

Toward #435, #436, #437.

Author: tseaver

samples/samples/conftest.py

@@ -41,6 +41,17 @@ def spanner_client():
  return client.Client()
 
 
+def scrub_instance_ignore_not_found(to_scrub):
+ """Helper for func:`cleanup_old_instances`"""
+ try:
+ for backup_pb in to_scrub.list_backups():
+ backup.Backup.from_pb(backup_pb, to_scrub).delete()
+
+ to_scrub.delete()
+ except exceptions.NotFound:
+ pass
+
+
 @pytest.fixture(scope="session")
 def cleanup_old_instances(spanner_client):
  """Delete instances, created by samples, that are older than an hour."""
@@ -54,11 +65,7 @@ def cleanup_old_instances(spanner_client):
  create_time = int(inst.labels["created"])
 
  if create_time <= cutoff:
-
- for backup_pb in inst.list_backups():
- backup.Backup.from_pb(backup_pb, inst).delete()
-
- inst.delete()
+ scrub_instance_ignore_not_found(inst)
 
 
 @pytest.fixture(scope="module")
@@ -76,19 +83,15 @@ def instance_config(spanner_client):
 
 @pytest.fixture(scope="module")
 def sample_instance(
- spanner_client,
- cleanup_old_instances,
- instance_id,
- instance_config,
- sample_name,
+ spanner_client, cleanup_old_instances, instance_id, instance_config, sample_name,
 ):
  sample_instance = spanner_client.instance(
  instance_id,
  instance_config,
  labels={
  "cloud_spanner_samples": "true",
  "sample_name": sample_name,
- "created": str(int(time.time()))
+ "created": str(int(time.time())),
  },
  )
  retry_429 = retry.RetryErrors(exceptions.ResourceExhausted, delay=15)