How is Python itself tested?

Question

How is Python itself tested? Not, "How do I write unit tests in Python?" but "Where is the compliance suite against which CPython, Pypy, and so on run tests to assert they're Python version-X.Y conformant?"

The python website mentions pythontest.net, but that appears to be just a target for test facilities, not part of or a resource for the compliance suite itself.

Answer 1

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

• the PyPy copy of the suite.
• the Jython copy
• the IronPython test suite, which is a subset tuned to what IronPython supports (only a subset of the CPython standard library is included in IronPython)