gh-126349: Add context managers to turtle for fill, poly and no_animation

[MarieRoald]

Adds fill(), poly() and no_animation() context managers to turtle.py.

Co-authored-by: Yngve Mardal Moe 3531982+yngvem@users.noreply.github.com

• Issue: Turtle context managers for fill, poly and tracer #126349

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📚 Documentation preview 📚: https://cpython-previews--126350.org.readthedocs.build/en/126350/library/turtle.html

[Wulian233]

LGTM
Recommend adding to what's new 3.14.rst

[Eclips4]

Could you please add a note about these additions to the Doc/whatsnew/3.14.rst?

[hugovk]

We don't usually include things like "If you have Python 3.14 or later" because each set of docs relates to one specific Python version.

But perhaps it's okay here because turtle is often used by beginners who might read these docs but have 3.12 or 3.13 installed?

[yngvem]

That makes a lot of sense, but in this specific case I think it's useful. Many learners are at universities or schools with old versions of Python, and they might not be aware that there are several versions of Python. So I think it's useful to make it very clear that this is a new feature.

[erlend-aasland]

Sorry to reopen, but IMO this reads a little bit unexpected. How about something in the lines of:

Starting with Python 3.14, you can use [...] instead of [...].

What do you think?

[danielhollas]

Why the extra newline between this and the previous import statement?

[yngvem]

We have tried to address the review comments now 🙂

[picnixz]

Some final minor nitpicks. Otherwise looks great!

[picnixz]

Last one and I am good! (modulo Hugo's comment)

[picnixz]

I promise there really shouldn't have anything left for me. Thank you for your patience! (my reviews tend to have multiple parts depending on the hour when I do the review).

[MarieRoald]

I promise there really shouldn't have anything left for me. Thank you for your patience! (my reviews tend to have multiple parts depending on the hour when I do the review).

No worries, thanks a lot for the thorough review!

[erlend-aasland]

This looks good, but I have some remarks and nits. PTAL.

[erlend-aasland]

Sorry to reopen, but IMO this reads a little bit unexpected. How about something in the lines of:

Starting with Python 3.14, you can use [...] instead of [...].

What do you think?

[erlend-aasland]

This can also be written more compact. Though, I'm not sure it is more readable, so feel free to ignore this :)

Suggested change

	... dist = 2
	... for i in range(200):
	... fd(dist)
	... rt(90)
	... dist += 2
	... for dist in range(0, 400, 2):
	... fd(dist+2)
	... rt(90)

[erlend-aasland]

Ditto.

[hugovk]

Thanks!

[hugovk]

(Conflict resolved.)

@erlend-aasland Any more comments or good to merge?

[erlend-aasland]

Please use the unittest assert methods iso. the assert keyword. Ditto for the rest of the added tests.

[MarieRoald]

Good catch! We have fixed that for the two tests we added in this commit. Should we also clean up the two assertions from #123617 here or should we have that in a separate PR?

[erlend-aasland]

I'm fine with including them here.

[graingert]

It's a bit unusual to call the context manager protocol manually, also part of the context manager protocol handling is missing here. (processing the return value of __exit__)

Also because unittest.mock.patch is already a cmgr you can just return it

def patch_screen():
    """
    Patch turtle._Screen for testing without a display.

    We must patch the _Screen class itself instead of the _Screen
    instance because instantiating it requires a display.
    """
    return unittest.mock.patch(
        "turtle._Screen.__new__",
        **{
            "return_value.__class__": turtle._Screen,
            "return_value.mode.return_value": "standard",
        },
    )

[graingert]

the mock.patch context manager handling in the tests could be improved