Bug#817193: failing tests with v62: test_listing, test_diff test_gzip.py::test_metadata, test_ipk.py::test_metadata, test_java.py::test_diff

[Zbigniew Jędrzejewski-Szmek]

I noticed that I was missing ppudmp from my installation, so tests
were skipped.  Once it is installed, the ppu tests also fail. Looks
like a programming error, PpuFile is File, not FilesystemFile from a
quick look.

=================================== FAILURES ===================================
_____________________________ test_identification ______________________________

file1 = <<class 'diffoscope.comparators.binary.FilesystemFile'> /builddir/build/BUILD/diffoscope/tests/data/test1.ppu>

    @skip_unless_tools_exist('ppudump')
    def test_identification(file1):
>       assert isinstance(file1, PpuFile)
E       assert isinstance(<<class 'diffoscope.comparators.binary.FilesystemFile'> /builddir/build/BUILD/diffoscope/tests/data/test1.ppu>, PpuFile)

tests/comparators/test_ppu.py:46: AssertionError
__________________________________ test_diff ___________________________________

differences = []

    @skip_unless_tool_is_older_than('ppudump', ppudump_version, '3.0.0')
    def test_diff(differences):
>       print(differences[0].unified_diff)
E       IndexError: list index out of range

tests/comparators/test_ppu.py:58: IndexError
__________________________ test_compare_non_existing ___________________________

monkeypatch = <_pytest.monkeypatch.monkeypatch object at 0xf3f7c52c>
file1 = <<class 'diffoscope.comparators.binary.FilesystemFile'> /builddir/build/BUILD/diffoscope/tests/data/test1.ppu>

    @skip_unless_tool_is_older_than('ppudump', ppudump_version, '3.0.0')
    def test_compare_non_existing(monkeypatch, file1):
>       assert_non_existing(monkeypatch, file1, has_null_source=False)

tests/comparators/test_ppu.py:64: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

monkeypatch = <_pytest.monkeypatch.monkeypatch object at 0xf3f7c52c>
fixture = <<class 'diffoscope.comparators.binary.FilesystemFile'> /builddir/build/BUILD/diffoscope/tests/data/test1.ppu>
has_null_source = False, has_details = True

    def assert_non_existing(monkeypatch, fixture, has_null_source=True, has_details=True):
        monkeypatch.setattr(Config(), 'new_file', True)
        assert Config().new_file, "didnt get patched"
    
        difference = fixture.compare(NonExistingFile('/nonexisting', fixture))
    
        output_html(difference, print_func=print)
        output_text(difference, print_func=print)
    
        assert difference.source2 == '/nonexisting'
>       assert not has_details or len(difference.details) > 0
E       assert (not True or 0 > 0)
E        +  where 0 = len([])
E        +    where [] = <Difference /builddir/build/BUILD/diffoscope/tests/data/test1.ppu -- /nonexisting []>.details

tests/comparators/utils.py:79: AssertionError