pecan.jsonify v1.3 adjustment

From pecan v1.3, pecan.jsonify uses json.Encoder unconditionally so that
jsonifying mock fails.
Pecan v1.2 uses simplejson.Encoder as encoder which accidentally encodes
MagicMock as {} due to check of '_asdict' attributes.
Since pecan.jsonify uses __json__ magic method when it's defined,
add __json__ method to mocks to return {} as json encode.

Closes-bug: #1754978
Change-Id: Iac955a7de2a1b66b5b56a73f5cc8a4e75150f82e

neutron/tests/tools.py

@@ -146,6 +146,46 @@ def verify_mock_calls(mocked_call, expected_calls_and_values,
     mocked_call.assert_has_calls(expected_calls, any_order=any_order)
 
 
+def _make_magic_method(method_mock):
+    # NOTE(yamahata): new environment needs to be created to keep actual
+    # method_mock for each callables.
+    def __call__(*args, **kwargs):
+        value_mock = method_mock._orig___call__(*args, **kwargs)
+        value_mock.__json__ = lambda: {}
+        return value_mock
+
+    def _get_child_mock(**kwargs):
+        value_mock = method_mock._orig__get_child_mock(**kwargs)
+        value_mock.__json__ = lambda: {}
+        return value_mock
+
+    return __call__, _get_child_mock
+
+
+def make_mock_plugin_json_encodable(plugin_instance_mock):
+    # NOTE(yamahata): Make return value of plugin method json encodable
+    # e.g. the return value of plugin_instance.create_network() needs
+    # to be json encodable
+    # plugin instance      -> method    -> return value
+    # Mock                    MagicMock    Mock
+    # plugin_instance_mock    method_mock  value_mock
+    #
+    # From v1.3 of pecan, pecan.jsonify uses json.Encoder unconditionally.
+    # pecan v1.2 uses simplejson.Encoder which accidentally encodes
+    # Mock as {} due to check of '_asdict' attributes.
+    # pecan.jsonify uses __json__ magic method for encoding when
+    # it's defined, so add __json__ method to return {}
+    for method_mock in plugin_instance_mock._mock_children.values():
+        if not callable(method_mock):
+            continue
+
+        method_mock._orig___call__ = method_mock.__call__
+        method_mock._orig__get_child_mock = method_mock._get_child_mock
+        __call__, _get_child_mock = _make_magic_method(method_mock)
+        method_mock.__call__ = __call__
+        method_mock._get_child_mock = _get_child_mock
+
+
 def get_subscribe_args(*args):
     # NOTE(yamahata): from neutron-lib 1.9.1, callback priority was added.
     # old signature: (callback, resource, event)

neutron/tests/unit/api/v2/test_base.py

@@ -43,6 +43,7 @@ from neutron import quota
 from neutron.quota import resource_registry
 from neutron.tests import base
 from neutron.tests import fake_notifier
+from neutron.tests import tools
 from neutron.tests.unit import dummy_plugin
 from neutron.tests.unit import testlib_api
 
@@ -87,6 +88,7 @@ class APIv2TestBase(base.BaseTestCase):
         instance = self.plugin.return_value
         instance._NeutronPluginBaseV2__native_pagination_support = True
         instance._NeutronPluginBaseV2__native_sorting_support = True
+        tools.make_mock_plugin_json_encodable(instance)
 
         api = router.APIRouter()
         self.api = webtest.TestApp(api)

neutron/tests/unit/extensions/test_providernet.py

@@ -28,6 +28,7 @@ from neutron.api import extensions
 from neutron.api.v2 import router
 from neutron.extensions import providernet as pnet
 from neutron import quota
+from neutron.tests import tools
 from neutron.tests.unit.api import test_extensions
 from neutron.tests.unit.api.v2 import test_base
 from neutron.tests.unit import testlib_api
@@ -70,6 +71,7 @@ class ProvidernetExtensionTestCase(testlib_api.WebTestCase):
         instance.get_networks_count.return_value = 1
         # Register mock plugin and enable the 'provider' extension
         instance.supported_extension_aliases = ["provider"]
+        tools.make_mock_plugin_json_encodable(instance)
         directory.add_plugin(constants.CORE, instance)
         ext_mgr = ProviderExtensionManager()
         self.ext_mdw = test_extensions.setup_extensions_middleware(ext_mgr)