Rework plugin infrastructure to nix side-effects

This reworks the plugin infrastructure so as to remove module-loading
side-effects which were making things a pain in the ass to test.

With the new system, there's no auto-registering meta class. Instead
plugins do whatever they want and then specify a hooks dict that maps
hook names to callables for the things they're tying into. The most
common one (and the only one we've implemented so far) is "setup".

This also simplifies the sampleplugin a little by moving the code
to __init__.py.

1 files changed, 27 insertions, 30 deletions

diff --git a/mediagoblin/tests/test_pluginapi.py b/mediagoblin/tests/test_pluginapi.py
index c5c614f6..8c9c6a04 100644
--- a/mediagoblin/tests/test_pluginapi.py
+++ b/mediagoblin/tests/test_pluginapi.py
@@ -37,8 +37,8 @@ def with_cleanup(*modules_to_delete):
                     pass
             # The plugin cache gets populated as a side-effect of
             # importing, so it's best to clear it before and after a test.
-            pcache = pluginapi.PluginCache()
-            pcache.clear()
+            pman = pluginapi.PluginManager()
+            pman.clear()
             try:
                 return fun(*args, **kwargs)
             finally:
@@ -51,7 +51,7 @@ def with_cleanup(*modules_to_delete):
                         del sys.modules[module]
                     except KeyError:
                         pass
-                pcache.clear()
+                pman.clear()
 
         _with_cleanup_inner.__name__ = fun.__name__
         return _with_cleanup_inner
@@ -93,16 +93,14 @@ def test_no_plugins():
     mg_globals.app_config = cfg['mediagoblin']
     mg_globals.global_config = cfg
 
-    pcache = pluginapi.PluginCache()
+    pman = pluginapi.PluginManager()
     setup_plugins()
 
     # Make sure we didn't load anything.
-    eq_(len(pcache.plugin_classes), 0)
-    eq_(len(pcache.plugin_objects), 0)
+    eq_(len(pman.plugins), 0)
 
 
-@with_cleanup('mediagoblin.plugins.sampleplugin',
-              'mediagoblin.plugins.sampleplugin.main')
+@with_cleanup('mediagoblin.plugins.sampleplugin')
 def test_one_plugin():
     """Run setup_plugins with a single working plugin"""
     cfg = build_config([
@@ -115,22 +113,21 @@ def test_one_plugin():
     mg_globals.app_config = cfg['mediagoblin']
     mg_globals.global_config = cfg
 
-    pcache = pluginapi.PluginCache()
+    pman = pluginapi.PluginManager()
     setup_plugins()
 
-    # Make sure we only found one plugin class
-    eq_(len(pcache.plugin_classes), 1)
-    # Make sure the class is the one we think it is.
-    eq_(pcache.plugin_classes[0].__name__, 'SamplePlugin')
+    # Make sure we only found one plugin
+    eq_(len(pman.plugins), 1)
+    # Make sure the plugin is the one we think it is.
+    eq_(pman.plugins[0], 'mediagoblin.plugins.sampleplugin')
+    # Make sure there was one hook registered
+    eq_(len(pman.hooks), 1)
+    # Make sure _setup_plugin_called was called once
+    import mediagoblin.plugins.sampleplugin
+    eq_(mediagoblin.plugins.sampleplugin._setup_plugin_called, 1)
 
-    # Make sure there was one plugin created
-    eq_(len(pcache.plugin_objects), 1)
-    # Make sure we called setup_plugin on SamplePlugin
-    eq_(pcache.plugin_objects[0]._setup_plugin_called, 1)
 
-
-@with_cleanup('mediagoblin.plugins.sampleplugin',
-              'mediagoblin.plugins.sampleplugin.main')
+@with_cleanup('mediagoblin.plugins.sampleplugin')
 def test_same_plugin_twice():
     """Run setup_plugins with a single working plugin twice"""
     cfg = build_config([
@@ -144,15 +141,15 @@ def test_same_plugin_twice():
     mg_globals.app_config = cfg['mediagoblin']
     mg_globals.global_config = cfg
 
-    pcache = pluginapi.PluginCache()
+    pman = pluginapi.PluginManager()
     setup_plugins()
 
-    # Make sure we only found one plugin class
-    eq_(len(pcache.plugin_classes), 1)
-    # Make sure the class is the one we think it is.
-    eq_(pcache.plugin_classes[0].__name__, 'SamplePlugin')
-
-    # Make sure there was one plugin created
-    eq_(len(pcache.plugin_objects), 1)
-    # Make sure we called setup_plugin on SamplePlugin
-    eq_(pcache.plugin_objects[0]._setup_plugin_called, 1)
+    # Make sure we only found one plugin
+    eq_(len(pman.plugins), 1)
+    # Make sure the plugin is the one we think it is.
+    eq_(pman.plugins[0], 'mediagoblin.plugins.sampleplugin')
+    # Make sure there was one hook registered
+    eq_(len(pman.hooks), 1)
+    # Make sure _setup_plugin_called was called once
+    import mediagoblin.plugins.sampleplugin
+    eq_(mediagoblin.plugins.sampleplugin._setup_plugin_called, 1)