Verify the resources API extension is available.

Signed-off-by: Lee Trager <lee.trager@canonical.com>

pylxd/client.py

@@ -331,6 +331,7 @@ def trusted(self):
     @property
     def resources(self):
         if self._resource_cache is None:
+            self.assert_has_api_extension('resources')
             response = self.api.resources.get()
             if response.status_code != 200:
                 raise exceptions.ClientConnectionFailed()

pylxd/tests/test_client.py

@@ -282,20 +282,28 @@ def powerset(types):
 
     def test_resources(self):
         a_client = client.Client()
+        a_client.host_info['api_extensions'] = ['resources']
         response = mock.MagicMock(status_code=200)
         response.json.return_value = {'metadata': {
             'cpu': {},
         }}
         self.get.return_value = response
         self.assertIn('cpu', a_client.resources)
 
-    def test_resources_raises_exception(self):
+    def test_resources_raises_conn_failed_exception(self):
         a_client = client.Client()
+        a_client.host_info['api_extensions'] = ['resources']
         response = mock.MagicMock(status_code=400)
         self.get.return_value = response
         with self.assertRaises(exceptions.ClientConnectionFailed):
             a_client.resources
 
+    def test_resources_raises_api_extension_not_avail_exception(self):
+        a_client = client.Client()
+        a_client.host_info['api_extensions'] = []
+        with self.assertRaises(exceptions.LXDAPIExtensionNotAvailable):
+            a_client.resources
+
     def test_resources_uses_cache(self):
         a_client = client.Client()
         a_client._resource_cache = {'cpu': {}}