'``LintPackage.run`` reports only unfiltered errors and raises
``SystemExit``.
:param PackageTypes package_type: The type of package to test.
:param bytes expected_output: The expected output of the linting.'

def assert_lint(self, package_type, expected_output):

    destination_path = FilePath(self.mktemp())
    destination_path.makedirs()
    source_path = FilePath(self.mktemp())
    source_path.makedirs()
    source_path.child('Foo').touch()
    source_path.child('Bar').touch()
    BuildPackage(package_type=package_type, destination_path=destination_path, source_paths={source_path: FilePath('/foo/bar'), source_path.child('Foo'): FilePath('/opt/file')}, name='package-name', prefix=FilePath('/'), epoch='3', rpm_version=RPMVersion(version='0.3', release='0.dev.1'), license='Example', url='https://package.example/', vendor='Acme    Corporation', maintainer='Someone    <noreply@example.com>', architecture='all', description='Test    Package\n\nThe    description.', category='none', dependencies=[]).run()
    step = LintPackage(package_type=package_type, destination_path=destination_path, epoch='3', rpm_version=RPMVersion(version='0.3', release='0.dev.1'), package='package-name', architecture='all')
    step.output = StringIO()
    self.assertRaises(SystemExit, step.run)
    self.assertEqual(step.output.getvalue(), expected_output)
