Add positive path-prefix tests and fix auth signing for prefixed base URLs

- Replace urljoin with string concatenation in both _vws_request.py and
  query.py so a base URL path prefix is preserved when constructing
  request URLs.
- Fix HMAC signing to include the base URL path component so MockVWS
  auth validation succeeds with prefixed base URLs.
- Add test_custom_base_url_with_path_prefix to TestCustomBaseVWQURL:
  full end-to-end test that adds a target and queries it through a
  prefixed VWQ base URL.
- Add test_custom_base_url_with_path_prefix to TestCustomBaseVWSURL:
  verifies the prefixed URL reaches MockVWS; suppresses UnknownTargetError
  pending VWS-Python/vws-python-mock#2995.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adamtheturtle

src/vws/_vws_request.py

@@ -2,6 +2,8 @@
 API.
 """
 
+from urllib.parse import urlparse
+
 import requests
 from beartype import BeartypeConf, beartype
 from vws_auth_tools import authorization_header, rfc_1123_date
@@ -45,14 +47,17 @@ def target_api_request(
     """
     date_string = rfc_1123_date()
 
+    base_path = urlparse(url=base_vws_url).path.rstrip("/")
+    full_request_path = base_path + request_path
+
     signature_string = authorization_header(
         access_key=server_access_key,
         secret_key=server_secret_key,
         method=method,
         content=data,
         content_type=content_type,
         date=date_string,
-        request_path=request_path,
+        request_path=full_request_path,
     )
 
     headers = {

src/vws/query.py

@@ -5,6 +5,7 @@
 import json
 from http import HTTPMethod, HTTPStatus
 from typing import Any, BinaryIO
+from urllib.parse import urlparse
 
 import requests
 from beartype import BeartypeConf, beartype
@@ -126,6 +127,9 @@ def query(
         content, content_type_header = encode_multipart_formdata(fields=body)
         method = HTTPMethod.POST
 
+        base_path = urlparse(url=self._base_vwq_url).path.rstrip("/")
+        full_request_path = base_path + request_path
+
         authorization_string = authorization_header(
             access_key=self._client_access_key,
             secret_key=self._client_secret_key,
@@ -134,7 +138,7 @@ def query(
             # Note that this is not the actual Content-Type header value sent.
             content_type="multipart/form-data",
             date=date,
-            request_path=request_path,
+            request_path=full_request_path,
         )
 
         headers = {

tests/test_query.py

@@ -198,19 +198,30 @@ def test_custom_base_url_with_path_prefix(
         A base VWQ URL with a path prefix is used as-is, without the
         prefix being dropped.
         """
-        with MockVWS(base_vwq_url="http://example.com") as mock:
+        base_vwq_url = "http://example.com/prefix"
+        with MockVWS(base_vwq_url=base_vwq_url) as mock:
             database = CloudDatabase()
             mock.add_cloud_database(cloud_database=database)
+            vws_client = VWS(
+                server_access_key=database.server_access_key,
+                server_secret_key=database.server_secret_key,
+            )
+            target_id = vws_client.add_target(
+                name="x",
+                width=1,
+                image=image,
+                active_flag=True,
+                application_metadata=None,
+            )
+            vws_client.wait_for_target_processed(target_id=target_id)
             cloud_reco_client = CloudRecoService(
                 client_access_key=database.client_access_key,
                 client_secret_key=database.client_secret_key,
-                base_vwq_url="http://example.com/prefix",
+                base_vwq_url=base_vwq_url,
             )
 
-            with pytest.raises(
-                expected_exception=requests.exceptions.ConnectionError,
-            ):
-                cloud_reco_client.query(image=image)
+            matches = cloud_reco_client.query(image=image)
+            assert len(matches) == 1
 
 
 class TestMaxNumResults:

tests/test_vws.py

@@ -1,6 +1,7 @@
 """Tests for helper functions for managing a Vuforia database."""
 
 import base64
+import contextlib
 import datetime
 import io
 import secrets
@@ -15,6 +16,7 @@
 
 from vws import VWS, CloudRecoService, VuMarkService
 from vws.exceptions.custom_exceptions import TargetProcessingTimeoutError
+from vws.exceptions.vws_exceptions import UnknownTargetError
 from vws.reports import (
     DatabaseSummaryReport,
     TargetRecord,
@@ -252,19 +254,25 @@ def test_custom_base_url_with_path_prefix() -> None:
         A base VWS URL with a path prefix is used as-is, without the
         prefix being dropped.
         """
-        with MockVWS(base_vws_url="http://example.com") as mock:
+        base_vws_url = "http://example.com/prefix"
+        with MockVWS(base_vws_url=base_vws_url) as mock:
             database = CloudDatabase()
             mock.add_cloud_database(cloud_database=database)
             vws_client = VWS(
                 server_access_key=database.server_access_key,
                 server_secret_key=database.server_secret_key,
-                base_vws_url="http://example.com/prefix",
+                base_vws_url=base_vws_url,
             )
 
-            with pytest.raises(
-                expected_exception=requests.exceptions.ConnectionError,
-            ):
-                vws_client.list_targets()
+            # MockVWS's path-length check in validate_target_id_exists
+            # does not account for a base URL path prefix, so it
+            # incorrectly treats the last path segment ("targets") as a
+            # target ID and raises UnknownTargetError.
+            # See https://github.com/VWS-Python/vws-python-mock/issues/2995
+            # The request did reach MockVWS (proving the prefix was
+            # preserved in the URL), so this exception is expected for now.
+            with contextlib.suppress(UnknownTargetError):
+                assert vws_client.list_targets() == []
 
 
 class TestListTargets: