Unit testing

Python-sdbus provides several utilities to enable unit testing.

class sdbus.unittest.IsolatedDbusTestCase

Extension of unittest.IsolatedAsyncioTestCase from standard library.

Creates an isolated instance of session D-Bus. The D-Bus will be closed and cleaned up after tests are finished.

Requires dbus-daemon executable be installed.


from sdbus import DbusInterfaceCommonAsync, dbus_method_async
from sdbus.unittest import IsolatedDbusTestCase

class TestInterface(DbusInterfaceCommonAsync,

    @dbus_method_async("s", "s")
    async def upper(self, string: str) -> str:
        """Uppercase the input"""
        return string.upper()

def initialize_object() -> Tuple[TestInterface, TestInterface]:
    test_object = TestInterface()

    test_object_connection = TestInterface.new_proxy(
    "org.example.test", '/')

    return test_object, test_object_connection

class TestProxy(IsolatedDbusTestCase):
    async def asyncSetUp(self) -> None:
        await super().asyncSetUp()
        await self.bus.request_name_async("org.example.test", 0)

    async def test_method_kwargs(self) -> None:
        test_object, test_object_connection = initialize_object()

            await test_object_connection.upper('test'),
bus: SdBus

Bus instance connected to isolated D-Bus environment.

It is also set as a default bus.

assertDbusSignalEmits(signal, timeout=1)

Assert that a given signal was emitted at least once within the given timeout.

  • signal – D-Bus signal object. Can be a signal from either local or proxy object.

  • timeout (Union[int, float]) – Maximum wait time until first captured signal.

Should be used as an async context manager. The context manager exits as soon as first signal is captured.

The object returned by context manager has following attributes:

output: List[Any]

List of captured data.


async with self.assertDbusSignalEmits(test_object.test_signal) as signal_record:

self.assertEqual(["test"], signal_record.output)

New in version 0.12.0.