test: Add replay test for EU multi-regional routing in GenAI SDK

google/genai/tests/models/test_generate_content_multi_regional.py

@@ -0,0 +1,76 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import os
+
+import pytest
+
+from ... import _replay_api_client
+from ... import Client
+from ...models import Models
+from .. import pytest_helper
+
+
+pytestmark = pytest_helper.setup(
+    file=__file__,
+    globals_for_file=globals(),
+    test_method='models.generate_content',
+)
+
+
+def test_eu_location_routing_prediction_replay(client, request, monkeypatch):
+  """Tests that the SDK can route to the EU multi-regional endpoint."""
+  if not client._api_client.vertexai:
+    pytest.skip('Test requires Vertex AI')
+
+  mode = request.config.getoption('--mode')
+  if mode == 'tap':
+    mode = 'replay'
+
+  # The `client` fixture monkeypatches `Client._get_api_client` to always return
+  # the fixture's client, which binds to `us-central1` via the environment.
+  # To test `eu` routing, we bypass the mock by explicitly instantiating a
+  # ReplayApiClient and injecting it.
+  with monkeypatch.context() as m:
+    m.delenv('GOOGLE_CLOUD_LOCATION', raising=False)
+
+    replay_api_client = _replay_api_client.ReplayApiClient(
+        mode=mode,
+        replay_id='tests/models/generate_content_multi_regional/test_eu_location_routing_prediction_replay.vertex',
+        replays_directory=os.environ.get('GOOGLE_GENAI_REPLAYS_DIRECTORY'),
+        vertexai=True,
+        project=client._api_client.project,
+        location='eu',
+    )
+
+    eu_client = Client(vertexai=True)
+    eu_client._api_client = replay_api_client
+    eu_client._models = Models(replay_api_client)
+
+    try:
+      # 1. Verify that the SDK correctly resolved the EU REP base URL internally
+      assert (
+          eu_client._api_client._http_options.base_url
+          == 'https://aiplatform.eu.rep.googleapis.com/'
+      )
+
+      # 2. Test the dataplane prediction (generate_content) against EU endpoint
+      response = eu_client.models.generate_content(
+          model='gemini-3-flash-preview',
+          contents='Testing EU multi-regional endpoint routing.',
+      )
+      assert response is not None
+    finally:
+      eu_client.close()