unifyfs-stage fails to transfer in Travis; not on real machines

[craigsteffen]

System information

Type	Version/Name
Operating System
OS Version
Architecture	Travis build environment
UnifyFS Version	dev on 2020jun18

Describe the problem you're observing

The unit test 0700 fails when unifyfs-stage tries to transfer the file out of the unifyfs file system.

Describe how to reproduce the problem

Just put test 0700 in without "expect fail" and it will fail the overall tests.

Include any warning or errors or releveant debugging data

Here's the error message given by unifyfs-stage:

failed to transfer file (src=/tmp/tmp.FaQ7lHYYg4/mount/intermediate.file, dst=/tmp/tmp.FaQ7lHYYg4/stage_destination_0700/destination_0700.file): Bad file descriptor
data transfer failed (Bad file descriptor)

I have run these same tests on summitdev and Cameron has run them on one of the machines at Livermore, and they run fine. Somehow the Travis environment is tripping something up.

I'm creating this issue as a to-do to track this down.

[CamStan]

Adding a reference to #511 for quick access to where this work was done.

Also noting that this test was changed to use the test_might_fail directive to essentially label it as "unstable."

[jenest]

There is one stage test currently set as test_might_fail, but I don't recall why this decision was made. Might have been a failure that only showed up on Travis and not locally and never got debugged on Travis.

UnifyFS/t/0700-unifyfs-stage-full.t

Lines 60 to 62 in b5d723d

	test_expect_success "final output is identical to initial input" '
	test_might_fail test_cmp ${UNIFYFS_TEST_TMPDIR}/stage_source/source_0700.file ${UNIFYFS_TEST_TMPDIR}/stage_destination_0700/destination_0700.file
	'

Essentially, even if this test fails on Travis, it will show as passing, which is something we should probably adjust in the long run.

Originally posted by @CamStan in #614 (comment)

9300-unifyfs-stage-isolated.t and 0700-unifyfs-stage-full.t fail on Summit and seem to be set as test_might_fail so that they pass on Travis. This might be a separate issue, and if so, I can create another.

[craigsteffen]

This is being addressed in the discussion of PR 614.

Jenna and I talked yesterday. She'll be creating a separate branch and PR to deal with this once PR 614 has gone in.

As far as we can tell in our testing on Summit, the test_might_fail tag can removed harmlessly.