Lazy load plugin list

This will allow us to wait for jenkins to come up properly before getting
this list. Otherwise we'd have to duplicate the error handling logic.

Change-Id: I663bf32e53e917284d93422526078b4dcf76e9c1

jenkins_jobs/builder.py

@@ -730,11 +730,13 @@ class Builder(object):
         self.cache = CacheStorage(jenkins_url, flush=flush_cache)
         self.global_config = config
         self.ignore_cache = ignore_cache
+        self._plugins_list = plugins_list
 
-        if plugins_list is None:
+    @property
-            self.plugins_list = self.jenkins.get_plugins_info()
+    def plugins_list(self):
-        else:
+        if self._plugins_list is None:
-            self.plugins_list = plugins_list
+            self._plugins_list = self.jenkins.get_plugins_info()
+        return self._plugins_list
 
     def load_files(self, fn):
         self.parser = YamlParser(self.global_config, self.plugins_list)

tests/builder/test_builder.py

@@ -0,0 +1,41 @@
+# vim: set fileencoding=utf-8 :
+#
+#  - Copyright 2014 Guido Günther <agx@sigxcpu.org>
+#
+# 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
+
+import jenkins_jobs.builder
+
+from testtools import TestCase
+
+
+class TestCaseTestBuilder(TestCase):
+    def setUp(self):
+        self.builder = jenkins_jobs.builder.Builder(
+            'http://jenkins.example.com',
+            'doesnot', 'matter',
+            plugins_list=['plugin1', 'plugin2'],
+        )
+        TestCase.setUp(self)
+
+    def test_plugins_list(self):
+        self.assertEqual(self.builder.plugins_list, ['plugin1', 'plugin2'])
+
+    @mock.patch.object(jenkins_jobs.builder.jenkins.Jenkins,
+                       'get_plugins_info', return_value=['p1', 'p2'])
+    def test_plugins_list_from_jenkins(self, jenkins_mock):
+        # Trigger fetching the plugins from jenkins when accessing the property
+        self.builder._plugins_list = None
+        self.assertEqual(self.builder.plugins_list, ['p1', 'p2'])