File Organization

• One class per file in workflow/.
• New modules under src/google/adk/ are private by default — see the visibility reference for the naming rules and how to expose a public symbol.

File Headers

Every module under src/google/adk/ starts with:

1. The Apache 2.0 license header (added by the addlicense hook).
2. from __future__ import annotations.
3. Imports: standard library, third party, then relative.

from __future__ import annotations is checked by scripts/compliance_checks.py, which exempts __init__.py, version.py, tests/, and contributing/samples/.

Where tests go

Mirror the source path under tests/unittests/:

src/google/adk/tools/environment/_edit_file_tool.py
tests/unittests/tools/environment/test_edit_file_tool.py

When one source file needs several test files, use the source file name — without the leading underscore or extension — as a shared prefix:

src/google/adk/workflow/_workflow.py
tests/unittests/workflow/test_workflow.py
tests/unittests/workflow/test_workflow_hitl.py
tests/unittests/workflow/test_workflow_nested.py