Retry target setup reads without recreating targets

tests/mock_vws/fixtures/api_contract.py

@@ -2,6 +2,7 @@
 
 import base64
 import binascii
+import contextlib
 import io
 import uuid
 from dataclasses import dataclass
@@ -12,13 +13,19 @@
 from tenacity.retry import retry_if_not_result
 from tenacity.stop import stop_after_attempt
 from vws import VWS, CloudRecoService
-from vws.reports import TargetStatuses
+from vws.exceptions.custom_exceptions import TargetProcessingTimeoutError
+from vws.exceptions.vws_exceptions import (
+    TargetStatusProcessingError,
+    UnknownTargetError,
+)
+from vws.reports import TargetStatusAndRecord, TargetStatuses
 
 from mock_vws.database import CloudDatabase
 from tests.mock_vws.utils import Endpoint, ModelTargetEndpoint
 from tests.mock_vws.utils.retries import (
     RETRY_ON_TARGET_NOT_YET_VISIBLE,
     RETRY_ON_TRANSIENT_VWS_FAILURE,
+    TRANSIENT_VWS_EXCEPTIONS,
 )
 
 # The number of targets to add before giving up on getting one which
@@ -107,16 +114,20 @@ def _add_target(*, vws_client: VWS, image: io.BytesIO) -> str:
 
 
 @beartype
+@RETRY_ON_TRANSIENT_VWS_FAILURE
 @RETRY_ON_TARGET_NOT_YET_VISIBLE
-def _wait_for_target_processed(*, vws_client: VWS, target_id_: str) -> None:
-    """Wait for a target to finish processing.
+def _get_processed_target(
+    *, vws_client: VWS, target_id_: str
+) -> TargetStatusAndRecord:
+    """Wait for and read a known target without repeating its creation.
 
     Real Vuforia sometimes reports a target which it has just created as
     unknown, because the target is not yet visible to the read path. We know
     the target exists, because Vuforia gave us its ID, so we retry rather
     than fail.
     """
     vws_client.wait_for_target_processed(target_id=target_id_)
+    return vws_client.get_target_record(target_id=target_id_)
 
 
 @dataclass(frozen=True, kw_only=True)
@@ -136,7 +147,6 @@ def _target_processed_successfully(result: _TargetProcessingResult) -> bool:
 
 
 @beartype
-@RETRY_ON_TRANSIENT_VWS_FAILURE
 @retry(
     retry=retry_if_not_result(predicate=_target_processed_successfully),
     stop=stop_after_attempt(max_attempt_number=_TARGET_SUCCESS_ATTEMPTS),
@@ -157,11 +167,27 @@ def _add_target_which_processed_successfully(
         The ID and processing status of the added target.
     """
     target_id_ = _add_target(vws_client=vws_client, image=image)
-    _wait_for_target_processed(
-        vws_client=vws_client,
-        target_id_=target_id_,
-    )
-    target_details = vws_client.get_target_record(target_id=target_id_)
+    try:
+        target_details = _get_processed_target(
+            vws_client=vws_client,
+            target_id_=target_id_,
+        )
+    except (
+        *TRANSIENT_VWS_EXCEPTIONS,
+        UnknownTargetError,
+        TargetProcessingTimeoutError,
+    ):  # pragma: no cover
+        # Setup owns the target until it can return it to the test. Cleanup
+        # is best effort: transient failures, a processing target, or one
+        # already gone must not hide the setup error.
+        # The real adapter also clears remaining targets before the next test.
+        with contextlib.suppress(
+            *TRANSIENT_VWS_EXCEPTIONS,
+            TargetStatusProcessingError,
+            UnknownTargetError,
+        ):
+            vws_client.delete_target(target_id=target_id_)
+        raise
     # Failed processing is nondeterministic against the live service.
     if target_details.status != TargetStatuses.SUCCESS:
         vws_client.delete_target(target_id=target_id_)  # pragma: no cover