`doctest._SpoofOut.truncate()` is passing None to `seek()` when the size argument is not given.

[aaron-fl]

Bug report

doctest._SpoofOut.truncate() is passing None to seek() when the size argument is not given.
You must pass an integer to seek.
So, if no size argument is given then simply truncate from the current position.

Linked PRs

• gh-102967: Don't pass None to seek(), simply truncate from the current position. #102968
• [3.15] gh-102967: Don't pass None to seek(), simply truncate from the current position (GH-102968) #155664
• [3.14] gh-102967: Don't pass None to seek(), simply truncate from the current position (GH-102968) #155665
• [3.13] gh-102967: Don't pass None to seek(), simply truncate from the current position (GH-102968) #155666

[AlexWaygood]

@arhadthedev, the tests label is for issues concerning bugs in CPython's internal test suite (usually these are files found in the Lib/test directory). This is a bug report concerning the doctest module, which is part of the standard library, not part of CPython's internal test suite.

[arhadthedev]

@AlexWaygood Thank you for clarification! I've thought the label is about the whole testing infrastructure some parts of which happen to be outside Lib/test for legacy reasons.