Add find_unique base manager method

Allows to request a single matched item from list of resources,
raising NotFound if no match was found or Conflict if more than one
match was found.

Change-Id: Ib8b516d96de2b95ae20eb4545db12c0b82651941
Closes-Bug: #1414953

saharaclient/api/base.py

@@ -69,6 +69,16 @@ class ResourceManager(object):
     def find(self, **kwargs):
         return [i for i in self.list() if _check_items(i, kwargs.items())]
 
+    def find_unique(self, **kwargs):
+        found = self.find(**kwargs)
+        if not found:
+            raise APIException(error_code=404,
+                               error_message=_("No matches found."))
+        if len(found) > 1:
+            raise APIException(error_code=409,
+                               error_message=_("Multiple matches found."))
+        return found[0]
+
     def _copy_if_defined(self, data, **kwargs):
         for var_name, var_value in six.iteritems(kwargs):
             if var_value is not None:

saharaclient/tests/unit/base.py

@@ -15,6 +15,7 @@
 import six
 import testtools
 
+from saharaclient.api import base
 from saharaclient.api import client
 
 from requests_mock.contrib import fixture
@@ -34,3 +35,13 @@ class BaseTestCase(testtools.TestCase):
     def assertFields(self, body, obj):
         for key, value in six.iteritems(body):
             self.assertEqual(value, getattr(obj, key))
+
+
+class TestResource(base.Resource):
+    resource_name = 'Test Resource'
+    defaults = {'description': 'Test Description',
+                'extra': "extra"}
+
+
+class TestManager(base.ResourceManager):
+    resource_class = TestResource

saharaclient/tests/unit/test_manager.py

@@ -0,0 +1,50 @@
+# Copyright (c) 2015 Mirantis Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import mock
+
+from saharaclient.api import base
+from saharaclient.tests.unit import base as test_base
+
+
+class ManagerTest(test_base.BaseTestCase):
+
+    def setUp(self):
+        super(ManagerTest, self).setUp()
+        self.man = test_base.TestManager(self.client)
+
+    def test_find(self):
+        self.man.list = mock.MagicMock(
+            return_value=[mock.Mock(test='foo'),
+                          mock.Mock(test='bar')]
+        )
+
+        self.assertEqual(2, len(self.man.find()))
+        self.assertEqual(1, len(self.man.find(test='foo')))
+        self.assertEqual(0, len(self.man.find(test='baz')))
+
+    def test_find_unique(self):
+        expected = mock.Mock(test='foo')
+        self.man.list = mock.MagicMock(
+            return_value=[expected,
+                          mock.Mock(test='bar')]
+        )
+
+        ex = self.assertRaises(base.APIException,
+                               self.man.find_unique, test='baz')
+        self.assertEqual(404, ex.error_code)
+        ex = self.assertRaises(base.APIException, self.man.find_unique)
+        self.assertEqual(409, ex.error_code)
+        self.assertEqual(expected, self.man.find_unique(test='foo'))

saharaclient/tests/unit/test_resource.py

@@ -15,20 +15,20 @@
 
 import testtools
 
-from saharaclient.api import base
+from saharaclient.tests.unit import base as test_base
 
 
 class ResourceTest(testtools.TestCase):
     def test_create_resource(self):
         dict = {"name": "test"}
-        resource = TestResource(None, dict)
+        resource = test_base.TestResource(None, dict)
         self.assertEqual("test", resource.name)
         self.assertEqual("Test Description", resource.description)
 
     def test_overwrite_default(self):
         dict = {"name": "test",
                 "description": "Changed Description"}
-        resource = TestResource(None, dict)
+        resource = test_base.TestResource(None, dict)
         self.assertEqual("test", resource.name)
         self.assertEqual("Changed Description", resource.description)
         self.assertEqual("extra", resource.extra)
@@ -37,14 +37,14 @@ class ResourceTest(testtools.TestCase):
         dict = {"name": "test",
                 "description": "Changed Description"}
         dict_copy = dict.copy()
-        resource = TestResource(None, dict)
+        resource = test_base.TestResource(None, dict)
         self.assertIsNotNone(resource)
         self.assertEqual(dict_copy, dict)
 
     def test_resource_str(self):
         dict = {"name": "test",
                 "description": "Changed Description"}
-        resource = TestResource(None, dict)
+        resource = test_base.TestResource(None, dict)
         rstr = str(resource)
         self.assertIn(resource.resource_name, rstr)
         self.assertIn("name", rstr)
@@ -53,9 +53,3 @@ class ResourceTest(testtools.TestCase):
         self.assertNotIn("Test Description", rstr)
         self.assertIn("extra", rstr)
         self.assertNotIn("manager", rstr)
-
-
-class TestResource(base.Resource):
-    resource_name = 'Test Resource'
-    defaults = {'description': 'Test Description',
-                'extra': "extra"}