pikepdf: pikepdf will have failed test with qpdf 10.6 but can be fixed without breaking compatibility

When running pikepdf’s tests against qpdf 10.6, the following failures occur:

b = b'\x7f'

    @given(binary())
    def test_codec_involution(b):
        # For all binary strings, there is a pdfdoc decoding. The encoding of that
        # decoding recovers the initial string. (However, not all str have a pdfdoc
        # encoding.)
>       assert b.decode('pdfdoc').encode('pdfdoc') == b
E       AssertionError: assert b'\x9f' == b'\x7f'
E         At index 0 diff: b'\x9f' != b'\x7f'
E         Use -v to get the full diff

and

s = '\x1f'

    @given(text())
    def test_break_encode(s):
        try:
            encoded_bytes = s.encode('pdfdoc')
        except ValueError as e:
            allowed_errors = [
                "'pdfdoc' codec can't encode character",
                "'pdfdoc' codec can't process Unicode surrogates",
                "'pdfdoc' codec can't encode some characters",
            ]
            if any((allowed in str(e)) for allowed in allowed_errors):
                return
            raise
        else:
>           assert encoded_bytes.decode('pdfdoc') == s
E           AssertionError: assert '˜' == '\x1f'
E             Strings contain only whitespace, escaping them using repr()
E             - '\x1f'
E             + '˜'

tests/test_codec.py:52: AssertionError

This is most likely because of qpdf/qpdf#606 which added previously omitted Unicode conversions for PDF Doc Encoding code points 0x18 through 0x1f and 0x7f. If you want to test mapping to an invalid code point, you can pick something lower than 0x18. That should map to the invalid character. Anyway, I’m not sure what correct fix is for your test.

I plan to release qpdf 10.6 most likely tomorrow, February 8. I plan on preparing everything today. Other than version numbers and final release mechanics, qpdf’s main is what 10.6 will look like. At this moment, I haven’t yet updated configure.ac and libtool versions, but I will be doing that shortly.