determine_packages should return a list of lists which the install hook should iterate over passing each inner list to apt_install in turn to ensure the dkms module gets install prior to openvswitch-switch trying to load it

hooks/neutron_ovs_hooks.py

@@ -31,7 +31,9 @@ CONFIGS = register_configs()
 @hooks.hook()
 def install():
     apt_update()
-    apt_install(determine_packages(), fatal=True)
+    pkgs = determine_packages()
+    for pkg in pkgs:
+        apt_install(pkg, fatal=True)
 
 
 @hooks.hook('neutron-plugin-relation-changed')

hooks/neutron_ovs_utils.py

@@ -29,12 +29,7 @@ TEMPLATES = 'templates/'
 
 
 def determine_packages():
-    ovs_pkgs = []
-    pkgs = neutron_plugin_attribute('ovs', 'packages',
-                                    'neutron')
-    for pkg in pkgs:
-        ovs_pkgs.extend(pkg)
-    return set(ovs_pkgs)
+    return neutron_plugin_attribute('ovs', 'packages', 'neutron')
 
 
 def register_configs(release=None):

unit_tests/test_neutron_ovs_hooks.py

@@ -45,7 +45,7 @@ class NeutronOVSHooksTests(CharmTestCase):
 
     def test_install_hook(self):
         _pkgs = ['foo', 'bar']
-        self.determine_packages.return_value = _pkgs
+        self.determine_packages.return_value = [_pkgs]
         self._call_hook('install')
         self.apt_update.assert_called_with()
         self.apt_install.assert_has_calls([

unit_tests/test_neutron_ovs_utils.py

@@ -54,7 +54,7 @@ class TestNeutronOVSUtils(CharmTestCase):
         _os_rel.return_value = 'trusty'
         _head_pkgs.return_value = head_pkg
         pkg_list = nutils.determine_packages()
-        expect = ['neutron-plugin-openvswitch-agent', head_pkg]
+        expect = [['neutron-plugin-openvswitch-agent'], [head_pkg]]
         self.assertItemsEqual(pkg_list, expect)
 
     def test_register_configs(self):