glib/gio/tests/memory-monitor-dbus.py.in
Philip Withnall 67a9fbf1fa tests: Wait for memory monitor to be able to handle signals before testing
This fixes a race condition which frequently caused the
`memory-monitor-dbus.py` test to fail.

The registration of the `LowMemoryMonitor` object on the bus, and the
`GMemoryMonitorDBus`’s connection to the warning signal raced, such that
it was possible for the mock `LowMemoryMonitor` to emit a warning signal
before the `GMemoryMonitorDBus` proxy was listening, and hence the proxy
would never see the signal.

Fix this by explicitly synchronising the two before proceeding to the
tests.

Make the same changes in the `memory-monitor-portal.py` test too, even
though that one was not failing. This should remove the need for a 2s
wait on every test run.

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

Fixes: #2887
2024-01-23 11:02:48 +00:00

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#!/usr/bin/python3
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 3 of the License, or (at your option) any
# later version. See http://www.gnu.org/copyleft/lgpl.html for the full text
# of the license.
__author__ = 'Bastien Nocera'
__email__ = 'hadess@hadess.net'
__copyright__ = '(c) 2019 Red Hat Inc.'
__license__ = 'LGPL 3+'
import unittest
import sys
import subprocess
import fcntl
import os
import taptestrunner
try:
# Do all non-standard imports here so we can skip the tests if any
# needed packages are not available.
import dbus
import dbus.mainloop.glib
import dbusmock
from gi.repository import GLib
from gi.repository import Gio
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
class TestLowMemoryMonitor(dbusmock.DBusTestCase):
'''Test GMemoryMonitorDBus'''
@classmethod
def setUpClass(klass):
klass.start_system_bus()
klass.dbus_con = klass.get_dbus(True)
def setUp(self):
try:
Gio.MemoryMonitor
except AttributeError:
raise unittest.SkipTest('Low memory monitor not in '
'introspection data. Requires '
'GObject-Introspection ≥ 1.63.2')
try:
(self.p_mock, self.obj_lmm) = self.spawn_server_template(
'low_memory_monitor', {}, stdout=subprocess.PIPE)
except ModuleNotFoundError:
raise unittest.SkipTest("Low memory monitor dbusmock template not "
"found. Requires dbusmock ≥ 0.18.4.")
# set log to nonblocking
flags = fcntl.fcntl(self.p_mock.stdout, fcntl.F_GETFL)
fcntl.fcntl(self.p_mock.stdout, fcntl.F_SETFL, flags | os.O_NONBLOCK)
self.last_warning = -1
self.dbusmock = dbus.Interface(self.obj_lmm, dbusmock.MOCK_IFACE)
try:
self.wait_for_bus_object('org.freedesktop.LowMemoryMonitor',
'/org/freedesktop/LowMemoryMonitor',
system_bus=True)
except:
raise
self.memory_monitor = Gio.MemoryMonitor.dup_default()
assert("GMemoryMonitorDBus" in str(self.memory_monitor))
self.memory_monitor.connect("low-memory-warning", self.memory_warning_cb)
self.mainloop = GLib.MainLoop()
self.main_context = self.mainloop.get_context()
# The LowMemoryMonitor API is stateless: it doesnt expose any
# properties, just a warning signal. Emit the signal in a loop until
# the GMemoryMonitor instance has initialised and synchronised to
# the right state.
def emit_warning(level):
self.dbusmock.EmitWarning(level)
return GLib.SOURCE_CONTINUE
idle_id = GLib.idle_add(emit_warning, 0)
while self.last_warning != 0:
self.main_context.iteration(True)
GLib.source_remove(idle_id)
def tearDown(self):
self.p_mock.terminate()
self.p_mock.wait()
def assertEventually(self, condition, message=None, timeout=5):
'''Assert that condition function eventually returns True.
Timeout is in seconds, defaulting to 5 seconds. message is
printed on failure.
'''
if not message:
message = 'timed out waiting for ' + str(condition)
def timed_out_cb(message):
self.fail(message)
return GLib.SOURCE_REMOVE
timeout_source = GLib.timeout_source_new_seconds(timeout)
timeout_source.set_callback(timed_out_cb, message)
timeout_source.attach(self.main_context)
while not condition():
self.main_context.iteration(True)
timeout_source.destroy()
def memory_warning_cb(self, monitor, level):
print("Received memory warning signal, level", level)
self.last_warning = level
self.main_context.wakeup()
def test_low_memory_warning_signal(self):
'''LowMemoryWarning signal'''
self.dbusmock.EmitWarning(100)
# Wait 2 seconds or until warning
self.assertEventually(lambda: self.last_warning == 100, "'100' low-memory warning not received", 2)
self.dbusmock.EmitWarning(255)
# Wait 2 seconds or until warning
self.assertEventually(lambda: self.last_warning == 255, "'255' low-memory warning not received", 2)
except ImportError as e:
@unittest.skip("Cannot import %s" % e.name)
class TestLowMemoryMonitor(unittest.TestCase):
def test_low_memory_warning_signal(self):
pass
if __name__ == '__main__':
unittest.main(testRunner=taptestrunner.TAPTestRunner())