add comments to tests/readme
This project uses unit, smoke and integration tests with Python files and notebooks. For more information, see a [quick introduction to unit, smoke and integration tests](https://miguelgfierro.com/blog/2018/a-beginners-guide-to-python-testing/). To manually execute the unit tests in the different environments, first **make sure you are in the correct environment as described in the [SETUP.md](/SETUP.md)**.
+Tests are automatically run as part of a DevOps pipeline. The pipelines are defined in .yml files in tests/ci with filenames that align with pipeline names.
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## Test execution
Click on the following menus to see more details on how to execute the unit, smoke and integration tests:
