Tests failed when flex is installed

[felixonmars]

Expected Behaviour

Tests should pass. Perhaps we should lower flex's preference or something? (Sorry I am not familiar with this...)

Actual Behaviour

Tests broken.

Steps to Reproduce

Install flex and run this project's test suite.

Environment

• OS: Arch Linux
• Python version: 3.9.6
• Backend: (flex, swagger-spec-validator or openapi-spec-validator) flex

ERROR tests/test_translating_parser.py::test_local_reference_from_root - pran...
ERROR tests/test_translating_parser.py::test_file_reference_from_root - pranc...
ERROR tests/test_translating_parser.py::test_local_reference_from_file - pran...
ERROR tests/test_translating_parser.py::test_same_file_reference_from_file - ...
ERROR tests/test_translating_parser.py::test_different_file_reference_from_file
ERROR tests/test_translating_parser.py::test_root_file_reference_from_file - ...
ERROR tests/test_translating_parser.py::test_root_file_reference_from_root - ...
ERROR tests/test_translating_parser.py::test_recursive_reference_in_root - pr...
ERROR tests/test_translating_parser.py::test_recursive_reference_in_file - pr...
ERROR tests/test_translating_parser.py::test_nested_recursive_reference_in_file
= 126 passed, 24 skipped, 3 xfailed, 32 xpassed, 264 warnings, 10 errors in 15.07s =

Example failure:

__________ ERROR at setup of test_nested_recursive_reference_in_file ___________

request = <SubRequest 'tester' for <Function test_nested_recursive_reference_in_file>>

    @fixture
    def tester(request):
        pattern = r"test_(.+)"
        test_function_name = request.node.name
        name_match = match(pattern, test_function_name)
        test_name = name_match[1]

        file_name = f"{test_name}.spec.yaml"
        path = join("tests", "specs", "translating_parser", file_name)
>       return SpecificationTester(path)

tests/test_translating_parser.py:18:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
tests/test_translating_parser.py:46: in __init__
    parser = _TranslatingParser(url)
prance/__init__.py:116: in __init__
    self.parse()
prance/__init__.py:146: in parse
    self._validate()
prance/__init__.py:334: in _validate
    BaseParser._validate(self)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <prance._TranslatingParser object at 0x7f6b4467dc40>

    def _validate(self):
        # Ensure specification is a mapping
        from collections.abc import Mapping

        if not isinstance(self.specification, Mapping):
            raise ValidationError("Could not parse specifications!")

        # Ensure the selected backend supports the given spec version
        versions, validator_name = BaseParser.BACKENDS[self.backend]

        # Fetch the spec version. Note that this is the spec version the spec
        # *claims* to be; we later set the one we actually could validate as.
        spec_version = None
        if spec_version is None:
            spec_version = self.specification.get("openapi", None)
        if spec_version is None:
            spec_version = self.specification.get("swagger", None)
        if spec_version is None:
            raise ValidationError(
                "Could not determine specification schema " "version!"
            )

        # Try parsing the spec version, examine the first component.
        import distutils.version

        parsed = distutils.version.StrictVersion(spec_version).version
        if parsed[0] not in versions:
>           raise ValidationError(
                'Version mismatch: selected backend "%s"'
                " does not support specified version %s!" % (self.backend, spec_version)
            )
E           prance.ValidationError: Version mismatch: selected backend "flex" does not support specified version 3.0.3!

prance/__init__.py:175: ValidationError

[leonpros]

EDIT:
issue resolved by NOT using flex (although it is default), but using openapi-spec-validator
prance validate --backend=openapi-spec-validator --no-resolve openapi

did you resolve this issue?
reproduced using python 3
prance 0.22.11.4.0
flex 6.14.1
for openapi 3.0.3