Make sure dashboard has a default panel group

According to the Horizon documentation for Settings and Configuration,
for a plugin panel, 'If you want the panel to show up without a panel
group, use the panel group “default”'. In some cases, plugin panels were
getting put under the panel group "Other" instead. This is because
the default panel group wasn't getting created during plugin panel
processing when the panel's dashboard class already had some panel
groups defined. Fix this by making sure a default panel group is created
in each dashboard.

Change-Id: I98064c434326aabec16b5d1631e360643609ed40
Closes-Bug: 1403094

horizon/base.py

@@ -46,6 +46,8 @@ from horizon.decorators import require_perms  # noqa
 from horizon import loaders
 
 
+# Name of the panel group for panels to be displayed without a group.
+DEFAULT_PANEL_GROUP = 'default'
 LOG = logging.getLogger(__name__)
 
 
@@ -335,7 +337,7 @@ class PanelGroup(object):
     """
     def __init__(self, dashboard, slug=None, name=None, panels=None):
         self.dashboard = dashboard
-        self.slug = slug or getattr(self, "slug", "default")
+        self.slug = slug or getattr(self, "slug", DEFAULT_PANEL_GROUP)
         self.name = name or getattr(self, "name", None)
         # Our panels must be mutable so it can be extended by others.
         self.panels = list(panels or getattr(self, "panels", []))
@@ -561,6 +563,7 @@ class Dashboard(Registry, HorizonComponent):
             self.panels = [self.panels]
 
         # Now iterate our panel sets.
+        default_created = False
         for panel_set in self.panels:
             # Instantiate PanelGroup classes.
             if not isinstance(panel_set, collections.Iterable) and \
@@ -573,7 +576,14 @@ class Dashboard(Registry, HorizonComponent):
             # Put our results into their appropriate places
             panels_to_discover.extend(panel_group.panels)
             panel_groups.append((panel_group.slug, panel_group))
+            if panel_group.slug == DEFAULT_PANEL_GROUP:
+                default_created = True
 
+        # Plugin panels can be added to a default panel group. Make sure such a
+        # default group exists.
+        if not default_created:
+            default_group = PanelGroup(self)
+            panel_groups.insert(0, (default_group.slug, default_group))
         self._panel_groups = collections.OrderedDict(panel_groups)
 
         # Do the actual discovery

openstack_dashboard/test/test_panels/another_panel/panel.py

@@ -0,0 +1,18 @@
+#    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 horizon
+
+
+class AnotherPanel(horizon.Panel):
+    name = "Another Plugin Panel"
+    slug = 'another_panel'

openstack_dashboard/test/test_panels/another_panel/templates/another_panel/index.html

@@ -0,0 +1,11 @@
+{% extends 'base.html' %}
+{% load i18n %}
+{% block title %}Another Plugin-based Panel{% endblock %}
+
+{% block main %}
+<div class="row">
+  <div class="col-sm-12">
+    Another Plugin-based Panel
+  </div>
+</div>
+{% endblock %}

openstack_dashboard/test/test_panels/another_panel/urls.py

@@ -0,0 +1,21 @@
+#    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.
+
+from django.conf.urls import patterns
+from django.conf.urls import url
+
+from openstack_dashboard.test.test_panels.another_panel import views
+
+urlpatterns = patterns(
+    '',
+    url(r'^$', views.IndexView.as_view(), name='index'),
+)

openstack_dashboard/test/test_panels/another_panel/views.py

@@ -0,0 +1,20 @@
+#    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.
+
+from django.utils.translation import ugettext_lazy as _
+
+from horizon import views
+
+
+class IndexView(views.HorizonTemplateView):
+    template_name = 'admin/another_panel/index.html'
+    page_title = _("Another Plugin-based Panel")

openstack_dashboard/test/test_plugins/panel_group_config/_50_admin_add_panel_to_default_group.py

@@ -0,0 +1,10 @@
+# The name of the panel to be added to HORIZON_CONFIG. Required.
+PANEL = 'another_panel'
+# The name of the dashboard the PANEL associated with. Required.
+PANEL_DASHBOARD = 'admin'
+# The name of the panel group the PANEL is associated with.
+PANEL_GROUP = 'default'
+
+# Python panel class of the PANEL to be added.
+ADD_PANEL = \
+    'openstack_dashboard.test.test_panels.another_panel.panel.AnotherPanel'

openstack_dashboard/test/test_plugins/panel_group_tests.py

@@ -18,6 +18,8 @@ from django.test.utils import override_settings
 import horizon
 
 from openstack_dashboard.test import helpers as test
+from openstack_dashboard.test.test_panels.another_panel \
+    import panel as another_panel
 from openstack_dashboard.test.test_panels.plugin_panel \
     import panel as plugin_panel
 from openstack_dashboard.test.test_panels.second_panel \
@@ -76,3 +78,10 @@ class PanelGroupPluginTests(test.PluginTestCase):
     def test_unregistered_panel_group(self):
         dashboard = horizon.get_dashboard("admin")
         self.assertIsNone(dashboard.get_panel_group("nonexistent_panel"))
+
+    def test_add_panel_to_default_panel_group(self):
+        dashboard = horizon.get_dashboard('admin')
+        default_panel_group = dashboard.get_panel_group('default')
+        self.assertIsNotNone(default_panel_group)
+        self.assertIn(another_panel.AnotherPanel,
+                      [p.__class__ for p in default_panel_group])