Eric Sunshine [off-list ref] writes:

On Wed, Apr 21, 2021 at 12:55 PM Eric Sunshine [off-list ref] wrote:

quoted

    count_ls_files 5 -s &&
    count_ls_files 3 -u &&
    count_ls_files 1 -u one~HEAD &&
    ...

The nice thing about having a helper function is that it can clean up
after itself by not leaving a new file lying around, thus you wouldn't
have to make adjustments to the expected number of untracked files (as
mentioned in the commit message). If this is the sort of thing which
comes up often enough (if there are more such cases beyond the two
scripts you changed in this series), then it might make sense to
promote the helper function to test-lib-functions.sh.

The frequency with which this idiom crops up with commands beyond
git-ls-files suggests the more general solution of supporting it
directly in test-lib-functions.sh for any command. For instance:

    test_cmd_line_count = 3 git ls-files -u &&

Or, perhaps, a new mode of test_line_count():

    test_line_count = 3 -c git ls-files -u &&

That looks nice on paper, but may be going too far.

We may want to count the lines in the error message, or we may want
to count the lines after filtering the output with pipe.

A test file that is dedicated to test ls-files with a file local
helper "count_ls_files" smells like a better place to stop, at least
to me.