Merge branch 'L2SS-551-multi-meta' into 'master'

L2SS-551: Do not combine ABCMeta with Tango DeviceMeta

Closes L2SS-551

See merge request !206

tangostationcontrol/tangostationcontrol/devices/abstract_device.py

-# -*- coding: utf-8 -*-
-#
-# This file is part of the XXX project
-#
-#
-#
-# Distributed under the terms of the APACHE license.
-# See LICENSE.txt for more info.
-
-"""Abstract Device Meta for LOFAR2.0
-
-"""
-
-import logging
-
-from tango.server import DeviceMeta
-
-logger = logging.getLogger()
-
-
-# TODO(Corne): Fix combining metaclasses by iterating over their variables and
-#              methods. https://support.astron.nl/jira/browse/L2SS-551
-# class AbstractDeviceMetas(DeviceMeta, ABCMeta):
-class AbstractDeviceMetas(DeviceMeta):
-    """Collects meta classes to allow lofar_device to be both a Device and an ABC. """
-
-    def __new__(mcs, name, bases, namespace, **kwargs):
-        cls = DeviceMeta.__new__(mcs, name, bases, namespace, **kwargs)
-        # temp_cls = ABCMeta.__new__(mcs, name, bases, namespace)
-        # setattr(cls, '__abstractmethods__', temp_cls.__abstractmethods__)
-        # setattr(cls, '_abc_impl', temp_cls._abc_impl)
-        return cls

tangostationcontrol/tangostationcontrol/devices/lofar_device.py

@@ -11,10 +11,8 @@
 
 """
 
-from abc import abstractmethod
-
 # PyTango imports
-from tango.server import Device, command, attribute
+from tango.server import attribute, command, Device, DeviceMeta
 from tango import AttrWriteType, DevState, DebugIt, Attribute, DeviceProxy
 import time
 import math
@@ -23,7 +21,6 @@ import math
 from tangostationcontrol.clients.attribute_wrapper import attribute_wrapper
 from tangostationcontrol.common.lofar_logging import log_exceptions
 from tangostationcontrol.common.lofar_version import get_version
-from tangostationcontrol.devices.abstract_device import AbstractDeviceMetas
 from tangostationcontrol.devices.device_decorators import only_in_states, fault_on_error
 
 
@@ -32,7 +29,8 @@ __all__ = ["lofar_device"]
 import logging
 logger = logging.getLogger()
 
-class lofar_device(Device, metaclass=AbstractDeviceMetas):
+
+class lofar_device(Device, metaclass=DeviceMeta):
     """
 
     **Properties:**
@@ -217,14 +215,12 @@ class lofar_device(Device, metaclass=AbstractDeviceMetas):
     def configure_for_fault(self):
         pass
 
-    @abstractmethod
     def configure_for_off(self):
         pass
 
     def configure_for_on(self):
         pass
 
-    @abstractmethod
     def configure_for_initialise(self):
         pass
 

tangostationcontrol/tangostationcontrol/devices/opcua_device.py

@@ -24,7 +24,8 @@ from tangostationcontrol.devices.lofar_device import lofar_device
 import logging
 logger = logging.getLogger()
 
-__all__ = ["opcua_device", "main"]
+__all__ = ["opcua_device"]
+
 
 class opcua_device(lofar_device):
     """

tangostationcontrol/tangostationcontrol/devices/sdp/statistics.py

@@ -11,8 +11,6 @@
 
 """
 
-from abc import abstractmethod
-
 # PyTango imports
 from tango.server import device_property
 
@@ -32,15 +30,13 @@ import numpy
 
 __all__ = ["Statistics"]
 
-# TODO(Corne): Make Statistics use ABCMeta again when L2SS-551 is fixed
-#              https://support.astron.nl/jira/browse/L2SS-551
+
 class Statistics(opcua_device):
 
     # In derived classes, set this to a subclass of StatisticsCollector
     @property
-    @abstractmethod
     def STATISTICS_COLLECTOR_CLASS(self):
-        pass
+        raise NotImplementedError
 
     # -----------------
     # Device Properties

tangostationcontrol/tangostationcontrol/devices/sdp/xst.py

@@ -28,6 +28,7 @@ import numpy
 
 __all__ = ["XST", "main"]
 
+
 class XST(Statistics):
 
     STATISTICS_COLLECTOR_CLASS = XSTCollector

tangostationcontrol/tangostationcontrol/test/devices/test_abstract_device.py

-# -*- coding: utf-8 -*-
-#
-# This file is part of the LOFAR 2.0 Station Software
-#
-#
-#
-# Distributed under the terms of the APACHE license.
-# See LICENSE.txt for more info.
-
-import abc
-from unittest import mock
-
-from tango import server
-from tango.server import attribute
-
-from tangostationcontrol.devices.abstract_device import AbstractDeviceMetas
-
-from tangostationcontrol.test import base
-
-
-class TestAbstractDevice(base.TestCase):
-
-    class AbstractExample(object, metaclass=abc.ABCMeta):
-        """A pure abc.ABCMeta metaclass with an abstract method
-
-        This is an abstract class that inherits object with the abc.ABCMeta as
-        metaclass
-        """
-
-        @abc.abstractmethod
-        def example_method(self):
-            raise NotImplementedError
-
-    class TestHardwareDevice(server.Device, metaclass=AbstractDeviceMetas):
-        """This is your overarching abstract class with a combined metaclass
-
-        Device is an object with DeviceMeta as metaclass
-        We use HardwareDeviceMetas as metaclass
-
-        Our metaclass contract is now fulfilled.
-        """
-
-        @attribute(dtype=float)
-        def call_example_method(self):
-            return self.example_method()
-
-        @abc.abstractmethod
-        def example_method(self):
-            raise NotImplementedError
-
-    class ConcreteHardwareDevice(TestHardwareDevice):
-
-        def example_method(self):
-            return 12
-
-    def setUp(self):
-        super(TestAbstractDevice, self).setUp()
-
-    # def test_instance_tango(self):
-    #
-    #     try:
-    #         with DeviceTestContext(self.TestHardwareDevice, process=True) as proxy:
-    #             # Calling this method raises the NotImplementedError exception
-    #             proxy.call_example_method()
-    #     except Exception as e:
-    #         self.assertIsInstance(e, RuntimeError)
-    #
-    #     with DeviceTestContext(self.ConcreteHardwareDevice, process=True) as proxy:
-    #         self.assertEqual(12, proxy.call_example_method)
-
-    @mock.patch.object(server, 'get_worker')
-    @mock.patch.object(server, 'LatestDeviceImpl')
-    def test_instance_error(self, m_worker, m_implement):
-        # Creating this object should raise a type error but it does not
-        # combining metaclasses in this way does not have the desired result.
-        # This is a known limitation of this approach
-        m_device = self.TestHardwareDevice(mock.Mock(), mock.Mock())
-
-        # Raising the NotImplementedError works as expected, however.
-        self.assertRaises(NotImplementedError, m_device.example_method)
-
-        # Creating this object of a class that has a pure metaclass does raise
-        # the expected error.
-        self.assertRaises(TypeError, self.AbstractExample)
-
-    @mock.patch.object(server, 'get_worker')
-    @mock.patch.object(server, 'LatestDeviceImpl')
-    def test_isinstance(self, m_worker, m_implement):
-        m_device = self.TestHardwareDevice(mock.Mock(), mock.Mock())
-
-        self.assertFalse(isinstance(m_device, AbstractDeviceMetas))

tangostationcontrol/tangostationcontrol/test/devices/test_statistics_device.py

+# -*- coding: utf-8 -*-
+#
+# This file is part of the LOFAR 2.0 Station Software
+#
+#
+#
+# Distributed under the terms of the APACHE license.
+# See LICENSE.txt for more info.
+
+import mock
+
+from tango import server
+from tango.test_context import DeviceTestContext
+
+from tangostationcontrol.test import base
+
+
+class TestStatisticsDevice(base.TestCase):
+
+    def setUp(self):
+        super(TestStatisticsDevice, self).setUp()
+
+    def test_python_bug(self):
+        """Python is bugged and super() calls in ctypes fail
+
+        This is the same type of issues that prevents combining metaclasses
+        DeviceMeta and ABCMeta
+
+        https://github.com/waveform80/picamera/issues/355
+        https://bugs.python.org/issue29270
+        """
+        import ctypes as ct
+
+        try:
+            class TestSubclass(ct.c_uint32):
+                def __repr__(self):
+                    return super().__repr__()
+        except Exception as e:
+            self.assertIsInstance(e, TypeError)
+
+    @mock.patch.object(server, 'get_worker')
+    def test_instance_statistics(self, m_worker):
+        """Test that we can import and create a statistics device
+
+        The import of Statistics fails when both ABCMeta and DeviceMeta are
+        combined. Leave this test to prevent regressions when reattempting our
+        combined metaclass.
+        """
+
+        from tangostationcontrol.devices.sdp.statistics import Statistics
+
+        with DeviceTestContext(Statistics, process=True) as proxy:
+            self.assertTrue(proxy.ping() > 0)