The GitLab CI ubuntu_test job has occasionally been failing like this,
perhaps once every few weeks or so.
[ RUN ] My/SupportedFileSystemsTest.CreateAndReadUUID/reiser4
test_SupportedFileSystems.cc:569: Failure
Expected: (m_partition.uuid.size()) >= (9U), actual: 0 vs 9
[ FAILED ] My/SupportedFileSystemsTest.CreateAndReadUUID/reiser4, where GetParam() = 24 (17 ms)
[----------] 1 test from My/SupportedFileSystemsTest (17 ms total)
Turns out there are 2 bugs in resier4progs. One causes debugfs.reiser4
to report a null UUID if the first byte of the UUID happens to be zero
[1], and the other cases mkfs.resier4 to write a corrupted UUID,
sometimes a null (all zeros) UUID [2].
There is a 1 in 256 chance of getting a null UUID [2] when creating and
reading a reiser4 file system, hence the occasional failure of the CI
job. The centos_test job isn't affected because CentOS doesn't have the
reiser4progs package.
Fix this by detecting when reiser4 reports a null UUID and assign a
dummy UUID to make the test pass. This does mean that there is a 1 in
256 chance of not detecting a true failure. However that still means
there is a 255 in 256 chance of detecting a true failure. That's good
odds. When a null UUID is detected for a reiser4 file system the test
output looks like this:
[ RUN ] My/SupportedFileSystemsTest.CreateAndReadUUID/reiser4
test_SupportedFileSystems.cc:580: Ignore test failure of a null UUID.
[ OK ] My/SupportedFileSystemsTest.CreateAndReadUUID/reiser4 (46 ms)
[1] 4802cdb18a
Fix up repair_master_print()
[2] 44cc024f39
Stop occasionally making file systems with null UUIDs
Closes#145 - Sporadic failure of test case
My/SupportedFileSystemsTest.CreateAndReadUUID/reiser4
975d9ecdc9