[Python-apps-team] Bug#844081: khal: FTBFS randomly (test_default_calendar fails)

[Santiago Vila]

Package: src:khal
Version: 0.8.4-1
Severity: serious

Dear maintainer:

I tried to build this package in stretch with "dpkg-buildpackage -A"
(which is what the "Arch: all" autobuilder would do to build it)
but it failed:

--------------------------------------------------------------------------------
[...]
 debian/rules build-indep
dh build-indep --with python3,sphinxdoc --buildsystem=pybuild
   dh_testdir -i -O--buildsystem=pybuild
   dh_update_autotools_config -i -O--buildsystem=pybuild
   dh_auto_configure -i -O--buildsystem=pybuild
I: pybuild base:184: python3.5 setup.py config 
running config
   debian/rules override_dh_auto_build
make[1]: Entering directory '/<<PKGBUILDDIR>>'
dh_auto_build
I: pybuild base:184: /usr/bin/python3 setup.py build 
running build
running build_py

[... snipped ...]

tests/aux_test.py ...................ss
tests/backend_test.py ..........................
tests/cal_display_test.py ..s...
tests/cli_test.py .....x.............
tests/controller_test.py ....
tests/event_test.py ..............................
tests/khalendar_aux_test.py .s......s..........s............
tests/khalendar_test.py ....................F.
tests/settings_test.py ........
tests/terminal_test.py ...
tests/vtimezone_test.py ...
tests/ui/test_calendarwidget.py ..s
tests/ui/test_widgets.py .

=================================== FAILURES ===================================
____________________________ test_default_calendar _____________________________

coll_vdirs = (<khal.khalendar.khalendar.CalendarCollection object at 0x7f485fcae400>, {'foobar': <FilesystemStorage(**{'path': '/tm...r1/private'})>, 'work': <FilesystemStorage(**{'path': '/tmp/pytest-of-buildd/pytest-0/test_default_calendar1/work'})>})

    def test_default_calendar(coll_vdirs):
        """test if an update to the vdir is detected by the CalendarCollection"""
        coll, vdirs = coll_vdirs
        vdir = vdirs['foobar']
        event = coll.new_event(event_today, 'foobar')
        vdir.upload(event)
        sleep(0.01)
        href, etag = list(vdir.list())[0]
        assert len(list(coll.get_events_on(today))) == 0
        coll.update_db()
        sleep(0.01)
>       assert len(list(coll.get_events_on(today))) == 1
E       assert 0 == 1
E        +  where 0 = len([])
E        +    where [] = list(<itertools.chain object at 0x7f4860b80860>)
E        +      where <itertools.chain object at 0x7f4860b80860> = <bound method CalendarCollection.get_events_on of <khal.khalendar.khalendar.CalendarCollection object at 0x7f485fcae400>>(datetime.date(2016, 11, 12))
E        +        where <bound method CalendarCollection.get_events_on of <khal.khalendar.khalendar.CalendarCollection object at 0x7f485fcae400>> = <khal.khalendar.khalendar.CalendarCollection object at 0x7f485fcae400>.get_events_on

tests/khalendar_test.py:335: AssertionError
========== 1 failed, 169 passed, 7 skipped, 1 xfailed in 2.68 seconds ==========
E: pybuild pybuild:276: test: plugin distutils failed with: exit code=1: cd /<<PKGBUILDDIR>>/.pybuild/pythonX.Y_3.5/build; python3.5 -m pytest tests
dh_auto_test: pybuild --test --test-pytest -i python{version} -p 3.5 returned exit code 13
debian/rules:26: recipe for target 'override_dh_auto_test' failed
make[1]: *** [override_dh_auto_test] Error 25
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
debian/rules:6: recipe for target 'build-indep' failed
make: *** [build-indep] Error 2
dpkg-buildpackage: error: debian/rules build-indep gave error exit status 2
--------------------------------------------------------------------------------

The relevant part of the build log is included above.
If you need full build logs, just say so, I have a lot of them.

The build was made on a QEMU/KVM virtual machine with a single CPU using sbuild.

The failure happens randomly. Sometimes it fails, sometimes it does not.
(I tried to build it 57 times and it failed 19 times).

Thanks.