freebsd --read-special test failure

[ThomasWaldmann]

the read-special test fails when reading the fifo on freebsd (master branch):

    freebsd64: __________________ ArchiverTestCase.test_create_read_special ___________________
    freebsd64: [gw0] freebsd10 -- Python 3.6.6 /vagrant/borg/borg/.tox/py36/bin/python
    freebsd64: self = <borg.testsuite.archiver.ArchiverTestCase testMethod=test_create_read_special>
    freebsd64:     def test_create_read_special(self):
    freebsd64:         self.create_regular_file('regular', size=1024)
    freebsd64:         os.symlink(os.path.join(self.input_path, 'file'), os.path.join(self.input_path, 'link_regular'))
    freebsd64:         if are_fifos_supported():
    freebsd64:             os.mkfifo(os.path.join(self.input_path, 'fifo'))
    freebsd64:             os.symlink(os.path.join(self.input_path, 'fifo'), os.path.join(self.input_path, 'link_fifo'))
    freebsd64:         self.cmd('init', '--encryption=repokey', self.repository_location)
    freebsd64:         archive = self.repository_location + '::test'
    freebsd64: >       self.cmd('create', '--read-special', archive, 'input')
    freebsd64: .tox/py36/lib/python3.6/site-packages/borg/testsuite/archiver.py:1791: 
    freebsd64: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
    freebsd64: .tox/py36/lib/python3.6/site-packages/borg/testsuite/archiver.py:292: in cmd
    freebsd64:     self.assert_equal(ret, exit_code)
    freebsd64: E   AssertionError: 1 != 0
    freebsd64: ----------------------------- Captured stdout call -----------------------------
    freebsd64: input/fifo: read: [Errno 35] Resource temporarily unavailable
    freebsd64: input/link_fifo: read: [Errno 35] Resource temporarily unavailable

[ThomasWaldmann]

Hmm, seems linux and macOS are happy reading a fifo that is not "fed", but freebsd is not.

How could --read-special be tested?

• we need to test that if follows symlinks for special files
• it will then read the "contents" of the special file
• special files are FIFOs, blk and chr devices
• we might be: not root, fakeroot or real root (depending on test env)
• the test should work on misc platforms and be relatively quick

[ThomasWaldmann]

guess we need to create a thread (or fork) that feeds the fifo with a small amount of data.
we can later compare if that data actually ended up in the borg archive.