def test_loopback_event(tmpdir):
listener = udev.MultipathListener()
received = threading.Event()
devices = []
def callback(device):
pprint.pprint({k: device[k] for k in device})
devices.append(device)
received.set()
listener._callback = callback
with running(listener):
# Create a backing file
filename = str(tmpdir.join("file"))
with open(filename, "wb") as f:
f.truncate(1024**2 * 10)
# Create and remove a loop device
with loopback.Device(filename) as loop:
print("Created a loop device at %r" % loop.path)
if not received.wait(1):
raise RuntimeError("Timeout receiving event")
# We expect an event about our loop device
assert devices[0].get("DEVNAME") == loop.path
def test_many_devices(self):
with namedTemporaryDir(dir="/tmp") as tmpdir:
filename = os.path.join(tmpdir, "file")
self.prepare_backing_file(filename)
for i in range(300):
with loopback.Device(filename) as device:
self.assertTrue(device.is_attached())
self.assertFalse(device.is_attached())
def test_with_device(self):
with namedTemporaryDir(dir="/tmp") as tmpdir:
filename = os.path.join(tmpdir, "file")
self.prepare_backing_file(filename)
with loopback.Device(filename) as device:
self.assertTrue(device.is_attached())
self.check_device(device)
self.assertFalse(device.is_attached())
self.check_backing_file(filename)
def test_supported(self):
with namedTemporaryDir() as tmpdir:
# Prepare backing file poisoned with "x"
backing_file = os.path.join(tmpdir, "backing_file")
with io.open(backing_file, "wb") as f:
f.write(b"x" * SIZE)
# Create a loop device
with loopback.Device(backing_file) as loop_device:
# And discard it
blockdev.discard(loop_device.path)
stat = os.stat(backing_file)
self.assertEqual(stat.st_blocks, 0)
def test_attach_detach_manually(self):
with namedTemporaryDir(dir="/tmp") as tmpdir:
filename = os.path.join(tmpdir, "file")
self.prepare_backing_file(filename)
device = loopback.Device(filename)
device.attach()
try:
self.assertTrue(device.is_attached())
self.check_device(device)
finally:
device.detach()
self.assertFalse(device.is_attached())
self.check_backing_file(filename)
def create_device(self, size):
"""
Create loop device of size bytes.
The block device is detached when the instance is closed.
"""
name = "backing-file-%03d" % next(self._count)
backing_file = os.path.join(self._tmpdir, name)
with open(backing_file, "w") as f:
f.truncate(size)
device = loopback.Device(backing_file)
device.attach()
self._devices.append(device)
return device.path
def loop_device(tmpdir):
backing_file = str(tmpdir.join("backing_file"))
with io.open(backing_file, "wb") as f:
f.write(b"x" * FILE_SIZE)
with loopback.Device(backing_file) as loop_device:
yield loop_device