chore: import upstream snapshot with attribution

examples/custom_provider_plugin/test_example_provider.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+# 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.
+
+"""Simple test for the custom provider plugin."""
+
+import os
+
+import dotenv
+# Import the provider to trigger registration with LangExtract
+# Note: This manual import is only needed when running without installation.
+# After `pip install -e .`, the entry point system handles this automatically.
+from langextract_provider_example import CustomGeminiProvider  # noqa: F401
+
+import langextract as lx
+
+
+def main():
+  """Test the custom provider."""
+  dotenv.load_dotenv(override=True)
+  api_key = os.getenv("GEMINI_API_KEY") or os.getenv("LANGEXTRACT_API_KEY")
+
+  if not api_key:
+    print("Set GEMINI_API_KEY or LANGEXTRACT_API_KEY to test")
+    return
+
+  config = lx.factory.ModelConfig(
+      model_id="gemini-3.5-flash",
+      provider="CustomGeminiProvider",
+      provider_kwargs={"api_key": api_key},
+  )
+  model = lx.factory.create_model(config)
+
+  print(f"✓ Created {model.__class__.__name__}")
+
+  # Test inference
+  prompts = ["Say hello"]
+  results = list(model.infer(prompts))
+
+  if results and results[0]:
+    print(f"✓ Inference worked: {results[0][0].output[:50]}...")
+  else:
+    print("✗ No response")
+
+
+if __name__ == "__main__":
+  main()