How is Python itself tested?

Question

How is Python itself tested? No, "How to write unit tests in Python?" but "Where is the matching package with which CPython, Pypy, etc. run tests to claim that they are versions of the Python version of XY?"

Pythontest.net is mentioned on the python website, but it seems to be just the target audience, not part or resource of the matching package itself.

Answer 1

The source code for CPython includes a test suite that is considered a compliance suite. This kit is used to test other Python implementations; see, for example:

• PyPy copy of the package .
• Jython copy
• IronPython test suite , which is a subset configured to support IronPython (only part of the standard CPython library is included in IronPython)