CI test failures, and how to deal with them

[hannesm]

The CI has several errors such as:

 test_gntshr alias test/runtest (exit 2)
(cd _build/default/test && ./test_gntshr.exe)
Failed to open grant share device: ENOENT
Does this system have Xen userspace grant share support?
On linux try:
  sudo modprobe xen-gntalloc
Fatal error: exception (Failure "Failed to open interface")

I'm not sure how we can deal with them? Should a ENOENT in the test considered to be ok? (at the price that we won't notice when all CI systems suddenly will return ENOENT, and we won't run the tests)?

[palainp]

Thank you @hannesm for the report. The message is displayed by #5. I have tried locally and it works (or at least it prints a lot of numbers from 0 to 10000). I don't know how to check if the xen package is installed on the test runners.