2.9.1: test_render_pdf fails on illumos

[Marcel Telka]

The test_render_pdf started to fail on illumos with the pipdeptree 2.9.1 release:

_______________________________ test_render_pdf ________________________________
    
tmp_path = PosixPath('/tmp/pytest-of-marcel/pytest-60/test_render_pdf0')
mocker = <pytest_mock.plugin.MockerFixture object at 0x7fffaa521a10>
  
    def test_render_pdf(tmp_path: Path, mocker: MockerFixture) -> None: 
        output = p.dump_graphviz(t, output_format="pdf")
        res = tmp_path / "file"
        with pytest.raises(OSError, match="Bad file descriptor"):  # noqa: PT012, SIM117 # because we reopen the file
            with res.open("wb") as buf:
                mocker.patch.object(sys, "stdout", buf)
>               p.print_graphviz(output)
E               OSError: [Errno 9] Bad file number

tests/test_pipdeptree.py:715: OSError

During handling of the above exception, another exception occurred:
  
tmp_path = PosixPath('/tmp/pytest-of-marcel/pytest-60/test_render_pdf0')
mocker = <pytest_mock.plugin.MockerFixture object at 0x7fffaa521a10>

    def test_render_pdf(tmp_path: Path, mocker: MockerFixture) -> None:
        output = p.dump_graphviz(t, output_format="pdf")
        res = tmp_path / "file"
        with pytest.raises(OSError, match="Bad file descriptor"):  # noqa: PT012, SIM117 # because we reopen the file
            with res.open("wb") as buf:
                mocker.patch.object(sys, "stdout", buf)
>               p.print_graphviz(output)
E               AssertionError: Regex pattern did not match.
E                Regex: 'Bad file descriptor'
E                Input: '[Errno 9] Bad file number'

tests/test_pipdeptree.py:715: AssertionError
------------------------------ Captured log call -------------------------------
DEBUG    graphviz.backend.execute:execute.py:61 run [PosixPath('dot'), '-Kdot', '-Tpdf']
DEBUG    graphviz.backend.execute:execute.py:61 run [PosixPath('dot'), '-Kdot', '-Tpdf']

The problem is that the test now expect linux-specific behavior. The difference between linux and illumos is easily visible using the following test (in C):

#include <stdio.h>
#include <string.h>
#include <errno.h>
int main(void)
{
        printf("%d: %s\n", EBADF, strerror(EBADF));
}

On linux it prints:

9: Bad file descriptor

On illumos it shows:

9: Bad file number