[#206] Fix exception when adding client instance to abstract class.

iota/api.py

@@ -107,6 +107,12 @@ def __getattr__(self, command):
             # noinspection PyTypeChecker
             return None
 
+        # Fix an error when invoking dunder methods.
+        # https://github.com/iotaledger/iota.lib.py/issues/206
+        if command.startswith("__"):
+            # noinspection PyUnresolvedReferences
+            return super(StrictIota, self).__getattr__(command)
+
         try:
             command_class = self.commands[command]
         except KeyError:

test/api_test.py

@@ -1,137 +1,154 @@
 # coding=utf-8
 from __future__ import absolute_import, division, print_function, \
-  unicode_literals
+    unicode_literals
 
+from abc import ABCMeta
 from unittest import TestCase
 
-from iota import InvalidCommand, Iota, StrictIota
+from six import with_metaclass
+
+from iota import InvalidCommand, StrictIota
 from iota.adapter import MockAdapter
 from iota.commands import CustomCommand
 from iota.commands.core.get_node_info import GetNodeInfoCommand
 
 
 class CustomCommandTestCase(TestCase):
-  def setUp(self):
-    super(CustomCommandTestCase, self).setUp()
+    def setUp(self):
+        super(CustomCommandTestCase, self).setUp()
 
-    self.name     = 'helloWorld'
-    self.adapter  = MockAdapter()
-    self.command  = CustomCommand(self.adapter, self.name)
+        self.name = 'helloWorld'
+        self.adapter = MockAdapter()
+        self.command = CustomCommand(self.adapter, self.name)
 
-  def test_call(self):
-    """
-    Sending a custom command.
-    """
-    expected_response = {'message': 'Hello, IOTA!'}
+    def test_call(self):
+        """
+        Sending a custom command.
+        """
+        expected_response = {'message': 'Hello, IOTA!'}
 
-    self.adapter.seed_response('helloWorld', expected_response)
+        self.adapter.seed_response('helloWorld', expected_response)
 
-    response = self.command()
+        response = self.command()
 
-    self.assertEqual(response, expected_response)
-    self.assertTrue(self.command.called)
+        self.assertEqual(response, expected_response)
+        self.assertTrue(self.command.called)
 
-    self.assertListEqual(
-      self.adapter.requests,
-      [{'command': 'helloWorld'}],
-    )
+        self.assertListEqual(
+            self.adapter.requests,
+            [{'command': 'helloWorld'}],
+        )
 
-  def test_call_with_parameters(self):
-    """
-    Sending a custom command with parameters.
-    """
-    expected_response = {'message': 'Hello, IOTA!'}
+    def test_call_with_parameters(self):
+        """
+        Sending a custom command with parameters.
+        """
+        expected_response = {'message': 'Hello, IOTA!'}
 
-    self.adapter.seed_response('helloWorld', expected_response)
+        self.adapter.seed_response('helloWorld', expected_response)
 
-    response = self.command(foo='bar', baz='luhrmann')
+        response = self.command(foo='bar', baz='luhrmann')
 
-    self.assertEqual(response, expected_response)
-    self.assertTrue(self.command.called)
+        self.assertEqual(response, expected_response)
+        self.assertTrue(self.command.called)
 
-    self.assertListEqual(
-      self.adapter.requests,
-      [{'command': 'helloWorld', 'foo': 'bar', 'baz': 'luhrmann'}],
-    )
+        self.assertListEqual(
+            self.adapter.requests,
+            [{'command': 'helloWorld', 'foo': 'bar', 'baz': 'luhrmann'}],
+        )
 
-  def test_call_error_already_called(self):
-    """
-    A command can only be called once.
-    """
-    self.adapter.seed_response('helloWorld', {})
-    self.command()
+    def test_call_error_already_called(self):
+        """
+        A command can only be called once.
+        """
+        self.adapter.seed_response('helloWorld', {})
+        self.command()
 
-    with self.assertRaises(RuntimeError):
-      self.command(extra='params')
+        with self.assertRaises(RuntimeError):
+            self.command(extra='params')
 
-    self.assertDictEqual(self.command.request, {'command': 'helloWorld'})
+        self.assertDictEqual(self.command.request, {'command': 'helloWorld'})
 
-  def test_call_reset(self):
-    """
-    Resetting a command allows it to be called more than once.
-    """
-    self.adapter.seed_response('helloWorld', {'message': 'Hello, IOTA!'})
-    self.command()
+    def test_call_reset(self):
+        """
+        Resetting a command allows it to be called more than once.
+        """
+        self.adapter.seed_response('helloWorld', {'message': 'Hello, IOTA!'})
+        self.command()
 
-    self.command.reset()
+        self.command.reset()
 
-    self.assertFalse(self.command.called)
-    self.assertIsNone(self.command.request)
-    self.assertIsNone(self.command.response)
+        self.assertFalse(self.command.called)
+        self.assertIsNone(self.command.request)
+        self.assertIsNone(self.command.response)
 
-    expected_response = {'message': 'Welcome back!'}
-    self.adapter.seed_response('helloWorld', expected_response)
-    response = self.command(foo='bar')
+        expected_response = {'message': 'Welcome back!'}
+        self.adapter.seed_response('helloWorld', expected_response)
+        response = self.command(foo='bar')
 
-    self.assertDictEqual(response, expected_response)
-    self.assertDictEqual(self.command.response, expected_response)
+        self.assertDictEqual(response, expected_response)
+        self.assertDictEqual(self.command.response, expected_response)
 
-    self.assertDictEqual(
-      self.command.request,
+        self.assertDictEqual(
+            self.command.request,
 
-      {
-        'command':  'helloWorld',
-        'foo':      'bar',
-      },
-    )
+            {
+                'command': 'helloWorld',
+                'foo': 'bar',
+            },
+        )
 
 
 class IotaApiTestCase(TestCase):
-  def test_init_with_uri(self):
-    """
-    Passing a URI to the initializer instead of an adapter instance.
-    """
-    api = StrictIota('mock://')
-    self.assertIsInstance(api.adapter, MockAdapter)
-
-  def test_registered_command(self):
-    """
-    Preparing a documented command.
-    """
-    api = StrictIota(MockAdapter())
-
-    # We just need to make sure the correct command type is
-    # instantiated; individual commands have their own unit tests.
-    command = api.getNodeInfo
-    self.assertIsInstance(command, GetNodeInfoCommand)
-
-  def test_unregistered_command(self):
-    """
-    Attempting to create an unsupported command.
-    """
-    api = StrictIota(MockAdapter())
-
-    with self.assertRaises(InvalidCommand):
-      # noinspection PyStatementEffect
-      api.helloWorld
-
-  def test_create_command(self):
-    """
-    Preparing an experimental/undocumented command.
-    """
-    api = StrictIota(MockAdapter())
-
-    custom_command = api.create_command('helloWorld')
-
-    self.assertIsInstance(custom_command, CustomCommand)
-    self.assertEqual(custom_command.command, 'helloWorld')
+    def test_init_with_uri(self):
+        """
+        Passing a URI to the initializer instead of an adapter instance.
+        """
+        api = StrictIota('mock://')
+        self.assertIsInstance(api.adapter, MockAdapter)
+
+    def test_registered_command(self):
+        """
+        Preparing a documented command.
+        """
+        api = StrictIota(MockAdapter())
+
+        # We just need to make sure the correct command type is
+        # instantiated; individual commands have their own unit tests.
+        command = api.getNodeInfo
+        self.assertIsInstance(command, GetNodeInfoCommand)
+
+    def test_unregistered_command(self):
+        """
+        Attempting to create an unsupported command.
+        """
+        api = StrictIota(MockAdapter())
+
+        with self.assertRaises(InvalidCommand):
+            # noinspection PyStatementEffect
+            api.helloWorld
+
+    def test_create_command(self):
+        """
+        Preparing an experimental/undocumented command.
+        """
+        api = StrictIota(MockAdapter())
+
+        custom_command = api.create_command('helloWorld')
+
+        self.assertIsInstance(custom_command, CustomCommand)
+        self.assertEqual(custom_command.command, 'helloWorld')
+
+    def test_use_in_abstract_class(self):
+        """
+        Tests a regression where adding a client instance to an abstract
+        class definition raises an exception.
+
+        References:
+            - https://github.com/iotaledger/iota.lib.py/issues/206
+        """
+        # This statement will raise an exception if the regression is
+        # present; no assertions necessary.
+        # noinspection PyUnusedLocal
+        class CustomClient(with_metaclass(ABCMeta)):
+            client = StrictIota(MockAdapter())