264 lines
10 KiB
Python
264 lines
10 KiB
Python
"""
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Module to mock out portions of the dbus library for testing purposes.
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This is intended to be used with doctest, something like::
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>>> from sugar.testing import mockdbus
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>>> mock_service = mockdbus.MockService(
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... 'service.name', '/service/path', name='printed_name')
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This doesn't actually change anything, yes; you must install the mock
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service to get it to run. This actually modifies the dbus module in
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place, and should only be used in a process dedicated to testing (you
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shouldn't use this in normal code). Next we install the service and
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get the interface::
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>>> mock_service.install()
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>>> import dbus
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>>> mock_interface = dbus.Interface(mock_service, 'interface.name')
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Before you trigger code that uses this mock service, you have to tell
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the service how to respond, like::
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>>> mock_interface.make_response('methodName', 'response')
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Next time mock_interface.methodName(any arguments) is called, it will
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return 'response'. Also, when that method is called it will print
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out the call plus the arguments. This works well with doctest, like::
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>>> mock_interface.methodName(1, 2)
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Called printed_name.interface.name:methodName(1, 2)
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'response'
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(Note: the first line is printed, the second line is the return value)
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It is an error if a method is called that has no response setup,
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unless that method is called asynchronously (with reply_handler).
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Then the reply_handler will be called as soon as the response has been
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created with service.make_response(). By delaying the response you
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can force response handlers to run out of order.
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"""
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import dbus
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_installed = False
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fake_get_object = None
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def _install():
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"""
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Installs the monkeypatch to dbus. Called automatically when
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necessary.
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"""
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global _installed, fake_get_object
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if _installed:
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return
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bus = dbus.SessionBus()
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old_get_object = bus.get_object
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fake_get_object = FakeGetObject(old_get_object)
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bus.get_object = fake_get_object
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_installed = True
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# XXX: Do we need to override bus.add_signal_receiver?
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class FakeGetObject(object):
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"""
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The replacement dbus.get_object() function/callable. This
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delegates to the real get_object callable, except when a
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MockService has been registered.
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"""
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def __init__(self, real_get_object):
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self._real_get_object = real_get_object
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self._overrides = {}
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def register(self, mock_service, service_name, path):
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"""
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Registers a MockService instance to the service_name and path.
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Calls to dbus.get_object(service_name, path) will now return
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this mock_service object.
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"""
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self._overrides[(service_name, path)] = mock_service
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def __call__(self, service_name, path):
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override = self._overrides.get((service_name, path), None)
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if override is None:
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return self._real_get_object(service_name, path)
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else:
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return override
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class MockService(object):
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"""
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A mock service object. You should first instantiate then install
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this object. Once installed, calls to
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dbus.get_object(service_name, path) will return this object
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instead of a real dbus service object.
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"""
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def __init__(self, service_name, path, name=None):
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self.service_name = service_name
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self.path = path
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if name is None:
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name = self.service_name
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self.name = name
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self._connections = {}
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self._pending_responses = {}
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self._pending_requests = {}
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def __repr__(self):
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if self.name == self.service_name:
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return '<%s %s:%s>' % (
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self.__class__.__name__,
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self.service_name, self.path)
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else:
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return '<%s %s %s:%s>' % (
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self.__class__.__name__,
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self.name,
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self.service_name, self.path)
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def install(self):
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"""
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Installs this object.
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"""
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_install()
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fake_get_object.register(
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self, self.service_name, self.path)
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def __getattr__(self, attr, dbus_interface=None):
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if attr == 'make_response':
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return BoundInterface(self.make_response, dbus_interface)
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return MockMethod(self, attr, dbus_interface)
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def call(self, meth_name, dbus_interface, *args, **kw):
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formatted = [repr(a) for a in args]
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formatted.extend(['%s=%r' % item for item in kw.items()])
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formatted = ', '.join(formatted)
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print 'Called %s.%s:%s(%s)' % (self.name, dbus_interface, meth_name, formatted)
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if 'reply_handler' in kw:
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reply_handler = kw.pop('reply_handler')
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else:
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reply_handler = None
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if 'error_handler' in kw:
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error_handler = kw.pop('error_handler')
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else:
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error_handler = None
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key = (meth_name, dbus_interface)
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if reply_handler:
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if key in self._pending_requests:
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raise ValueError(
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"Duplicate requests not yet handled for %s:%s" % (dbus_interface, meth_name))
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self._pending_requests[key] = (reply_handler, error_handler)
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self.call_reply_handlers()
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return
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assert error_handler is None, (
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"error_handler %s without reply_handler" % error_handler)
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if key not in self._pending_responses:
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if self._pending_responses:
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extra = '(have responses %s)' % self._response_description()
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else:
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extra = '(have no waiting responses)'
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raise ValueError(
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"You must call make_response() before %s:%s method "
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"is called %s"
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% (dbus_interface, meth_name, extra))
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error, response = self._pending_responses.pop(key)
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if error:
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# XXX: Is this how it should be raised?
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raise response
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else:
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return response
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def make_response(self, meth_name, response, error=False,
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dbus_interface=None):
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"""
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This is used to generate a response to a method call. If
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error is true, then the response object is an exception that
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will be raised (or passed to error_handler).
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"""
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key = (meth_name, dbus_interface)
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if key in self._pending_responses:
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raise ValueError(
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"A response %r is already registered for %s:%s"
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% (self._pending_responses[key], dbus_interface, meth_name))
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self._pending_responses[key] = (error, response)
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def _response_description(self):
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result = []
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for meth_name, dbus_interface in sorted(self._pending_responses.keys()):
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value = self._pending_responses[(meth_name, dbus_interface)]
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result.append('%s:%s()=%r' % (dbus_interface, meth_name, value))
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return ', '.join(result)
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def call_reply_handlers(self):
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"""
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This calls any reply_handlers that now have responses (or
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errors) ready for them. This can be called when a response is
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added after an asynchronous method is called, to trigger the
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response actually being called.
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"""
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# XXX: Should make_response automatically call this?
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for key in sorted(self._pending_responses.keys()):
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if key in self._pending_requests:
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error, response = self._pending_responses[key]
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reply_handler, error_handler = self._pending_requests[key]
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if error:
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# XXX: Is this how it should be raised?
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error_handler(response)
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else:
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reply_handler(response)
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del self._pending_responses[key]
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del self._pending_requests[key]
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def connect_to_signal(self, signal, handler_function,
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dbus_interface=None, **kw):
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self._connections.setdefault((signal, dbus_interface), []).append(
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handler_function)
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def send_signal(self, signal, dbus_interface=None):
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# XXX: This isn't really done
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for listener in self._connections.get((signal, dbus_interface), []):
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# XXX: Argument?
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listener()
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@property
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def empty(self):
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"""
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This can be called to at the end of the test to make sure
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there's no responses or requests left over.
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"""
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return (
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not self._pending_responses
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and not self._pending_requests)
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class MockMethod(object):
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def __init__(self, obj, meth_name, dbus_interface):
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self.obj = obj
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self.meth_name = meth_name
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self.dbus_interface = dbus_interface
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def __repr__(self):
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return '<%s.%s:%s method>' % (
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self.obj.name, self.meth_name, self.dbus_interface)
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def __call__(self, *args, **kw):
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return self.obj.call(
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self.meth_name, self.dbus_interface,
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*args, **kw)
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class BoundInterface(object):
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def __init__(self, method, dbus_interface):
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self.method = method
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self.dbus_interface = dbus_interface
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def __repr__(self):
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return '<bound interface %s for %s>' % (
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self.dbus_interface, self.method)
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def __call__(self, *args, **kw):
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kw.setdefault('dbus_interface', self.dbus_interface)
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return self.method(*args, **kw)
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