Merge https://github.com/google/adk-python/pull/6155
**Please ensure you have read the [contribution guide](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) before creating a pull request.**
### Link to Issue or Description of Change
**1. Link to an existing issue (if applicable):**
N/A
**2. Or, if no issue exists, describe the change:**
**Problem:**
The repository is missing Apache 2.0 license headers across 155 files. This is required by Google OSPO.
**Solution:**
Prepended the standard Apache 2.0 open-source license header to all flagged files. The copyright year was dynamically assigned based on each file's first commit year in git history.
### Testing Plan
_Please describe the tests that you ran to verify your changes. This is required for all PRs that are not small documentation or typo fixes._
**Unit Tests:**
- [ ] I have added or updated unit tests for my change.
- [x] All unit tests pass locally.
_Please include a summary of passed `pytest` results._
N/A - This PR only adds comments (license headers) to the top of files and contains zero functional code changes. No new tests are needed, and existing tests should pass as-is.
**Manual End-to-End (E2E) Tests:**
N/A - No functional code was changed.
### Checklist
- [x] I have read the [CONTRIBUTING.md](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) document.
- [x] I have performed a self-review of my own code.
- [ ] I have commented my code, particularly in hard-to-understand areas.
- [ ] I have added tests that prove my fix is effective or that my feature works.
- [x] New and existing unit tests pass locally with my changes.
- [ ] I have manually tested my changes end-to-end.
- [ ] Any dependent changes have been merged and published in downstream modules.
### Additional context
Co-authored-by: Shangjie Chen <deanchen@google.com>
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/6155 from milenvk:fix-missing-licenses d2a264b9a812fd997daf975ec37996e6b4b7a042
PiperOrigin-RevId: 936165783
FunctionTool._preprocess_args only converted dict args to a Pydantic
model for single-model and Optional[Model] annotations. A
Union[ModelA, ModelB] parameter was left as a raw dict, so
isinstance checks inside the tool failed with "Unexpected entity
type: <class 'dict'>"
Use pydantic.TypeAdapter to validate against the full Union so
pydantic picks the matching member. None and instances of any
declared union member pass through unchanged; instances of
unrelated BaseModels fall back to the existing graceful-failure
warning path.
Close#5799
Change-Id: Ie69f8efc8395162eac375a0eaad0c77ed2097cec
JSON test files generated by the agent test runner were missing trailing newlines, causing the pre-commit end-of-file-fixer hook to fail. Added an explicit newline write on serialization.
Change-Id: Idaffc4f2c23fa213f595ddef2188b0050aeb431d
Generated test JSON files for parallel_functions and pydantic_argument samples to verify their behavior.
Also fixed a test replay issue by ignoring timestamps in state (in agent_test_runner.py) to prevent false failures due to dynamic data.
Note: Some sample agents could not have tests generated successfully due to:
1. agent_tool_with_grounding_metadata: Fails on replay because AgentTool hides sub-agent events, causing mock LLM to get out of sync.
2. hello_world_stream_fc_args: Fails on rebuild because streaming function calls are not supported in the Unary API used by the test recorder.
3. output_schema_with_tools: Has external dependencies (Wikipedia/Google Search), making it unsuitable for automated regression tests without proper mocking.
Change-Id: I69df7daf49d175905dcbd85cf70914e460717915
George Weale