docs: clarify supported Python testing frameworks

README.md

@@ -99,7 +99,32 @@ Learn more about the rich features of the Python extension:
 -   [Environments](https://code.visualstudio.com/docs/python/environments): Automatically activate and switch between virtualenv, venv, pipenv, conda and pyenv environments.
 -   [Refactoring](https://code.visualstudio.com/docs/python/editing#_refactoring): Restructure your Python code with variable extraction and method extraction. Additionally, there is componentized support to enable additional refactoring, such as import sorting, through extensions including [isort](https://marketplace.visualstudio.com/items?itemName=ms-python.isort) and [Ruff](https://marketplace.visualstudio.com/items?itemName=charliermarsh.ruff).
 
+### Testing framework support
 
+The Python extension provides built-in integration with the VS Code Test Explorer
+for the following Python testing frameworks:
+
+- `unittest`
+- `pytest`
+
+These frameworks are directly supported through dedicated test discovery,
+execution, and result reporting implementations.
+
+#### Other testing frameworks (e.g. behave)
+
+Additional testing frameworks such as `behave` (BDD / Gherkin-style testing)
+are not currently supported out of the box.
+
+While these frameworks can still be executed manually via the terminal,
+they do not integrate with the VS Code Test Explorer at this time.
+
+Supporting additional frameworks would require:
+- Implementing test discovery logic
+- Mapping results to the VS Code Testing API
+- Long-term maintenance and ownership
+
+Community feedback helps prioritize which additional testing frameworks
+may be considered for future support.
 
 ## Supported locales