Self tests fail on postprocessors-> thumbnails

[mauricioquintela]

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• I'm reporting a bug unrelated to a specific site
• I've verified that I'm running yt-dlp version 2022.08.19 (update instructions) or later (specify commit)
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Building yt-dlp from source using aur package yt-dlp-git, self-test sequence fails at test/test_postprocessors.py::TestConvertThumbnail::test_escaping, preventing correct instalation.

Specifically, the error outputed from the self-test is:

===================================================== FAILURES ======================================================
________________________________________ TestConvertThumbnail.test_escaping _________________________________________

self = <test.test_postprocessors.TestConvertThumbnail testMethod=test_escaping>

    def test_escaping(self):
        pp = FFmpegThumbnailsConvertorPP()
        if not pp.available:
            print('Skipping: ffmpeg not found')
            return
    
        file = 'test/testdata/thumbnails/foo %d bar/foo_%d.{}'
        tests = (('webp', 'png'), ('png', 'jpg'))
    
        for inp, out in tests:
            out_file = file.format(out)
            if os.path.exists(out_file):
                os.remove(out_file)
>           pp.convert_thumbnail(file.format(inp), out)

test/test_postprocessors.py:56: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
yt_dlp/postprocessor/ffmpeg.py:1093: in convert_thumbnail
    self.real_run_ffmpeg(
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <yt_dlp.postprocessor.ffmpeg.FFmpegThumbnailsConvertorPP object at 0x7fb03a700250>
input_path_opts = [('test/testdata/thumbnails/foo %d bar/foo_%d.webp', ['-f', 'image2', '-pattern_type', 'none'])]
output_path_opts = [('test/testdata/thumbnails/foo %%d bar/foo_%%d.png', [])]

    def real_run_ffmpeg(self, input_path_opts, output_path_opts, *, expected_retcodes=(0,)):
        self.check_version()
    
        oldest_mtime = min(
            os.stat(encodeFilename(path)).st_mtime for path, _ in input_path_opts if path)
    
        cmd = [encodeFilename(self.executable, True), encodeArgument('-y')]
        # avconv does not have repeat option
        if self.basename == 'ffmpeg':
            cmd += [encodeArgument('-loglevel'), encodeArgument('repeat+info')]
    
        def make_args(file, args, name, number):
            keys = ['_%s%d' % (name, number), '_%s' % name]
            if name == 'o':
                args += ['-movflags', '+faststart']
                if number == 1:
                    keys.append('')
            args += self._configuration_args(self.basename, keys)
            if name == 'i':
                args.append('-i')
            return (
                [encodeArgument(arg) for arg in args]
                + [encodeFilename(self._ffmpeg_filename_argument(file), True)])
    
        for arg_type, path_opts in (('i', input_path_opts), ('o', output_path_opts)):
            cmd += itertools.chain.from_iterable(
                make_args(path, list(opts), arg_type, i + 1)
                for i, (path, opts) in enumerate(path_opts) if path)
    
        self.write_debug('ffmpeg command line: %s' % shell_quote(cmd))
        _, stderr, returncode = Popen.run(
            cmd, text=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
        if returncode not in variadic(expected_retcodes):
            self.write_debug(stderr)
>           raise FFmpegPostProcessorError(stderr.strip().splitlines()[-1])
E           yt_dlp.postprocessor.ffmpeg.FFmpegPostProcessorError: Conversion failed!

yt_dlp/postprocessor/ffmpeg.py:361: FFmpegPostProcessorError

Provide verbose output that clearly demonstrates the problem

• Run your yt-dlp command with -vU flag added (yt-dlp -vU <your command line>)
• Copy the WHOLE output (starting with [debug] Command-line config) and insert it below

Complete Verbose Output

Issue with self-test, preventing further installation of yt-dlp. As such, output of yt-dlp commands will be associated with last version that managed to build, instead of the one creating the issues.

[Lesmiscore]

My environment is able to pass this test

$ pytest test/test_postprocessors.py -k test_escaping
========================================= test session starts ==========================================
platform linux -- Python 3.9.13, pytest-6.2.4, py-1.10.0, pluggy-0.13.1 -- /home/linuxbrew/.linuxbrew/opt/python@3.9/bin/python3.9
cachedir: .pytest_cache
rootdir: /home/lesmi/yt-dlp, configfile: setup.cfg
plugins: parallel-0.1.0, timeout-1.4.2
collected 55 items / 54 deselected / 1 selected                                                        

test/test_postprocessors.py::TestConvertThumbnail::test_escaping PASSED                          [100%]

=================================== 1 passed, 54 deselected in 0.76s ===================================

Probably ffmpeg in your environment can't handle webp files, since yt-dlp uses ffmpeg to convert thumbnails

[pukkandan]

Same issue as #4604

[pukkandan]

Issue with self-test, preventing further installation of yt-dlp.

You will need to talk to the package maintainer about skipping the test during installation if needed