chore: import upstream snapshot with attribution

tests/unittests/utils/test_variant_utils.py

@@ -0,0 +1,43 @@
+# Copyright 2025 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.
+
+"""Tests for variant_utils."""
+
+import warnings
+
+from google.adk.utils import variant_utils
+from google.adk.utils.variant_utils import GoogleLLMVariant
+
+
+def test_get_google_llm_variant_enterprise(monkeypatch):
+  monkeypatch.setenv('GOOGLE_GENAI_USE_ENTERPRISE', 'true')
+  assert variant_utils.get_google_llm_variant() == GoogleLLMVariant.VERTEX_AI
+
+
+def test_get_google_llm_variant_vertexai_fallback(monkeypatch):
+  monkeypatch.delenv('GOOGLE_GENAI_USE_ENTERPRISE', raising=False)
+  monkeypatch.setenv('GOOGLE_GENAI_USE_VERTEXAI', 'true')
+  with warnings.catch_warnings(record=True) as w:
+    warnings.simplefilter('always')
+    result = variant_utils.get_google_llm_variant()
+    assert result == GoogleLLMVariant.VERTEX_AI
+    assert len(w) == 1
+    assert issubclass(w[-1].category, DeprecationWarning)
+    assert 'GOOGLE_GENAI_USE_VERTEXAI is deprecated' in str(w[-1].message)
+
+
+def test_get_google_llm_variant_default(monkeypatch):
+  monkeypatch.delenv('GOOGLE_GENAI_USE_ENTERPRISE', raising=False)
+  monkeypatch.delenv('GOOGLE_GENAI_USE_VERTEXAI', raising=False)
+  assert variant_utils.get_google_llm_variant() == GoogleLLMVariant.GEMINI_API