[MAINT] Rewrite write_tmp_imgs function and use it with pytest's tmp_path

[ymzayek]

Relates to #3935 (comment)

Changes proposed in this pull request:

• The function now looks like other testing helper functions that write data to disk by accepting a file_path argument. Now unit tests can pass it the pytest tmp_path fixture letting pytest take care of setting up a tmp directory and cleaning up the files.

[github-actions]

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[codecov]

Codecov Report

Merging #4094 (2acb067) into main (9ed165b) will increase coverage by 0.03%.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

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##             main    #4094      +/-   ##
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==========================================
  Files         143      143              
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  Branches     3357     3353       -4     
==========================================
- Hits        14773    14767       -6     
+ Misses        806      800       -6     
+ Partials      549      548       -1     

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macos-latest_3.11	91.54% <100.00%> (+0.03%)	⬆️
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Files	Coverage Δ
nilearn/_utils/testing.py	79.01% <100.00%> (+4.54%)	⬆️

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[Remi-Gau]

Except for the name change it looks good to me.

Thanks a bunch for taking care of this one.

Realizing that refactoring this context manager had been on my mind for a while, so defo happy to see it go.

[ymzayek]

I would like to rebase #3935 on this so hoping to merge soon. Another review would be great!

[bthirion]

I'm mostly happy with the PR, but ---again--- with the naming change from write_tmp_imgs to ẁrite_fake_imgs, as there is nothing in this function that implies that images are fake.

[Remi-Gau]

I guess that we could just call it write_imgs as they are not "fake" but they are not temporary unless when written in a tmp_dir

[ymzayek]

Yes makes sense. What about write_imgs_to_path?

[ymzayek]

I guess that we could just call it write_imgs as they are not "fake" but they are not temporary unless when written in a tmp_dir

Or yea just this one

[Remi-Gau]

either are ok with me

[bthirion]

LGTM, thx !