diff --git a/tests/mock_vws/content_length/test_incorrect.py b/tests/mock_vws/content_length/test_incorrect.py
index af8fc26ab..cef234693 100644
--- a/tests/mock_vws/content_length/test_incorrect.py
+++ b/tests/mock_vws/content_length/test_incorrect.py
@@ -11,13 +11,13 @@
 import pytest
 
 from mock_vws._constants import ResultCodes
-from tests.mock_vws.fixtures.vuforia_backends import VuforiaBackend
 from tests.mock_vws.utils import Endpoint
 from tests.mock_vws.utils.assertions import (
     assert_valid_date_header,
     assert_vwq_failure,
     assert_vws_failure,
 )
+from tests.mock_vws.utils.backend_capabilities import BackendCapabilities
 from tests.mock_vws.utils.too_many_requests import handle_server_errors
 
 
@@ -85,12 +85,14 @@ def test_not_integer(endpoint: Endpoint, base_vwq_url: str) -> None:
 
 def test_too_large(
     endpoint: Endpoint,
-    verify_mock_vuforia: VuforiaBackend,
+    backend_capabilities: BackendCapabilities,
     base_vwq_url: str,
 ) -> None:
     """An error is given if the given content length is too large."""
-    if verify_mock_vuforia is VuforiaBackend.REAL:
-        pytest.skip(reason="Real Vuforia takes too long to respond")
+    if not backend_capabilities.fast_oversized_content_length_response:
+        pytest.skip(
+            reason="This backend responds slowly to oversized Content-Length."
+        )
 
     if not bool(endpoint.headers.get("Content-Type")):
         pytest.skip(reason="No Content-Type header for this request")
diff --git a/tests/mock_vws/fixtures/vuforia_backends.py b/tests/mock_vws/fixtures/vuforia_backends.py
index e1c09cf9a..6c81935f6 100644
--- a/tests/mock_vws/fixtures/vuforia_backends.py
+++ b/tests/mock_vws/fixtures/vuforia_backends.py
@@ -33,6 +33,7 @@
     VuMarkCloudDatabase,
     get_model_target_credentials,
 )
+from tests.mock_vws.utils.backend_capabilities import BackendCapabilities
 from tests.mock_vws.utils.cloud_databases import AddCloudDatabase
 from tests.mock_vws.utils.model_target_retries import (
     retrying_transient_real_backend_failures,
@@ -883,3 +884,18 @@ def fixture_signed_model_target_credentials(
     return _model_target_credentials_for_backend(
         backend=verify_model_target_mock_vuforia,
     )
+
+
+@pytest.fixture(name="backend_capabilities")
+def fixture_backend_capabilities(
+    *,
+    verify_mock_vuforia: VuforiaBackend,
+) -> BackendCapabilities:
+    """The behavior supported by the running VWS and query backend."""
+    is_mock = verify_mock_vuforia != VuforiaBackend.REAL
+    return BackendCapabilities(
+        deterministic_target_order=is_mock,
+        deterministic_query_order=is_mock,
+        fast_oversized_content_length_response=is_mock,
+        rolling_rate_limit_window=is_mock,
+    )
diff --git a/tests/mock_vws/get_duplicates/test_duplicates.py b/tests/mock_vws/get_duplicates/test_duplicates.py
index f3f45e84c..c0dbfd18f 100644
--- a/tests/mock_vws/get_duplicates/test_duplicates.py
+++ b/tests/mock_vws/get_duplicates/test_duplicates.py
@@ -9,7 +9,7 @@
 from vws import VWS
 from vws.reports import TargetStatuses
 
-from tests.mock_vws.fixtures.vuforia_backends import VuforiaBackend
+from tests.mock_vws.utils.backend_capabilities import BackendCapabilities
 
 
 def test_duplicates(
@@ -136,7 +136,7 @@ def test_status(
 
 def test_order_is_upload_date_then_target_id(
     *,
-    verify_mock_vuforia: VuforiaBackend,
+    backend_capabilities: BackendCapabilities,
     high_quality_image: io.BytesIO,
     vws_client: VWS,
 ) -> None:
@@ -145,8 +145,10 @@ def test_order_is_upload_date_then_target_id(
     The real Vuforia Web Services do not document an order, so we do
     not verify this against them.
     """
-    if verify_mock_vuforia == VuforiaBackend.REAL:
-        pytest.skip(reason="The real Vuforia does not document an order.")
+    if not backend_capabilities.deterministic_target_order:
+        pytest.skip(
+            reason="This backend does not guarantee target upload-date order."
+        )
 
     target_ids = [
         vws_client.add_target(
diff --git a/tests/mock_vws/query/test_result_order.py b/tests/mock_vws/query/test_result_order.py
index be4824e8f..4b9a98d4f 100644
--- a/tests/mock_vws/query/test_result_order.py
+++ b/tests/mock_vws/query/test_result_order.py
@@ -8,18 +8,18 @@
 from vws import VWS
 
 from mock_vws.database import CloudDatabase
-from tests.mock_vws.fixtures.vuforia_backends import VuforiaBackend
 from tests.mock_vws.query.helpers import (
     query,
 )
 from tests.mock_vws.utils.assertions import (
     assert_query_success,
 )
+from tests.mock_vws.utils.backend_capabilities import BackendCapabilities
 
 
 def test_order_is_upload_date_then_target_id(
     *,
-    verify_mock_vuforia: VuforiaBackend,
+    backend_capabilities: BackendCapabilities,
     high_quality_image: io.BytesIO,
     vws_client: VWS,
     vuforia_database: CloudDatabase,
@@ -33,9 +33,9 @@ def test_order_is_upload_date_then_target_id(
     matcher, so we do not verify this against the real Vuforia Web
     Services.
     """
-    if verify_mock_vuforia == VuforiaBackend.REAL:
+    if not backend_capabilities.deterministic_query_order:
         pytest.skip(
-            reason="The real Query API uses Vuforia's match scores.",
+            reason="This backend does not guarantee query upload-date order.",
         )
 
     target_ids = [
@@ -72,7 +72,7 @@ def test_order_is_upload_date_then_target_id(
 
 def test_max_num_results_keeps_the_first_results(
     *,
-    verify_mock_vuforia: VuforiaBackend,
+    backend_capabilities: BackendCapabilities,
     high_quality_image: io.BytesIO,
     vws_client: VWS,
     vuforia_database: CloudDatabase,
@@ -84,9 +84,9 @@ def test_max_num_results_keeps_the_first_results(
     Which matches survive the truncation therefore does not vary
     between runs.
     """
-    if verify_mock_vuforia == VuforiaBackend.REAL:
+    if not backend_capabilities.deterministic_query_order:
         pytest.skip(
-            reason="The real Query API uses Vuforia's match scores.",
+            reason="This backend does not guarantee query upload-date order.",
         )
 
     target_ids = [
diff --git a/tests/mock_vws/target_list/test_rate_limit.py b/tests/mock_vws/target_list/test_rate_limit.py
index d70a08eb5..3d5aa2446 100644
--- a/tests/mock_vws/target_list/test_rate_limit.py
+++ b/tests/mock_vws/target_list/test_rate_limit.py
@@ -8,17 +8,15 @@
 from mock_vws._constants import ResultCodes
 from mock_vws.database import CloudDatabase
 from mock_vws.request_rate_limits import DOCUMENTED_REQUEST_RATE_LIMITS
-from tests.mock_vws.fixtures.vuforia_backends import (
-    VuforiaBackend,
-)
 from tests.mock_vws.utils import Endpoint
 from tests.mock_vws.utils.assertions import assert_vws_too_many_requests
+from tests.mock_vws.utils.backend_capabilities import BackendCapabilities
 
 
 def test_two_requests_per_minute(
     *,
     base_vws_url: str,
-    verify_mock_vuforia: VuforiaBackend,
+    backend_capabilities: BackendCapabilities,
     rate_limited_database: CloudDatabase,
 ) -> None:
     """A third ``GET /targets`` request within a minute is rate
@@ -66,7 +64,7 @@ def test_two_requests_per_minute(
         assert len(responses) <= limit.max_requests + 2
 
     status_codes = [response.status_code for response in responses]
-    if verify_mock_vuforia != VuforiaBackend.REAL:
+    if backend_capabilities.rolling_rate_limit_window:
         assert status_codes == [
             *[HTTPStatus.OK] * limit.max_requests,
             HTTPStatus.TOO_MANY_REQUESTS,
diff --git a/tests/mock_vws/target_list/test_target_list.py b/tests/mock_vws/target_list/test_target_list.py
index 8346144aa..3e1843152 100644
--- a/tests/mock_vws/target_list/test_target_list.py
+++ b/tests/mock_vws/target_list/test_target_list.py
@@ -6,9 +6,7 @@
 import pytest
 from vws import VWS
 
-from tests.mock_vws.fixtures.vuforia_backends import (
-    VuforiaBackend,
-)
+from tests.mock_vws.utils.backend_capabilities import BackendCapabilities
 
 
 def test_includes_targets(
@@ -32,7 +30,7 @@ def test_deleted(
 
 def test_order_is_upload_date_then_target_id(
     *,
-    verify_mock_vuforia: VuforiaBackend,
+    backend_capabilities: BackendCapabilities,
     high_quality_image: io.BytesIO,
     vws_client: VWS,
 ) -> None:
@@ -41,8 +39,10 @@ def test_order_is_upload_date_then_target_id(
     The real Vuforia Web Services do not document an order, so we do
     not verify this against them.
     """
-    if verify_mock_vuforia == VuforiaBackend.REAL:
-        pytest.skip(reason="The real Vuforia does not document an order.")
+    if not backend_capabilities.deterministic_target_order:
+        pytest.skip(
+            reason="This backend does not guarantee target upload-date order."
+        )
 
     target_ids = [
         vws_client.add_target(
diff --git a/tests/mock_vws/utils/backend_capabilities.py b/tests/mock_vws/utils/backend_capabilities.py
new file mode 100644
index 000000000..efb3c2e4c
--- /dev/null
+++ b/tests/mock_vws/utils/backend_capabilities.py
@@ -0,0 +1,29 @@
+"""Behavior declared by an adapter for the shared API tests."""
+
+from dataclasses import dataclass
+
+from beartype import beartype
+
+
+@beartype
+@dataclass(frozen=True, kw_only=True)
+class BackendCapabilities:
+    """The behavior and checks supported by the running service.
+
+    ``deterministic_target_order`` covers upload-date ordering for target
+    lists and duplicate lists. ``deterministic_query_order`` covers that
+    ordering for matches to identical images.
+
+    ``fast_oversized_content_length_response`` enables requests whose
+    declared body length exceeds their actual length. Services which wait
+    too long for the missing bytes cannot run that check.
+
+    ``rolling_rate_limit_window`` enables the exact request-sequence
+    assertion for a fresh database. Services with a fixed clock window
+    still run the common rate-limit assertions.
+    """
+
+    deterministic_target_order: bool
+    deterministic_query_order: bool
+    fast_oversized_content_length_response: bool
+    rolling_rate_limit_window: bool