diff --git a/abilian/services/activity/__init__.py b/abilian/services/activity/__init__.py
new file mode 100644
index 00000000..d8f183cc
--- /dev/null
+++ b/abilian/services/activity/__init__.py
@@ -0,0 +1,2 @@
+from .service import ActivityService
+from .models import ActivityEntry
\ No newline at end of file
diff --git a/abilian/services/activity.py b/abilian/services/activity/models.py
similarity index 59%
rename from abilian/services/activity.py
rename to abilian/services/activity/models.py
index 80f1b6ef..f340e108 100644
--- a/abilian/services/activity.py
+++ b/abilian/services/activity/models.py
@@ -16,9 +16,10 @@
 from sqlalchemy.types import Integer, DateTime, Text
 
 from abilian.core.entities import db, all_entity_classes
-from abilian.core.signals import activity
 from abilian.core.subjects import User
 
+__all__ = ['ActivityEntry']
+
 
 # TODO: review the design as it hits the DB with too many requests.
 class ActivityEntry(db.Model):
@@ -48,41 +49,3 @@ def object(self):
       if cls.__name__ == self.object_class:
         return cls.query.get(self.object_id)
     raise Exception("Unknown class: %s" % self.object_class)
-
-
-class ActivityService(object):
-
-  def __init__(self, app=None):
-    self.running = False
-    if app:
-      self.init_app(app)
-
-  def init_app(self, app):
-    self.app = app
-
-  def start(self):
-    assert not self.running
-    activity.connect(self.log_activity)
-    self.running = True
-
-  def stop(self):
-    assert self.running
-    activity.disconnect(self.log_activity)
-    self.running = False
-
-  def log_activity(self, sender, actor, verb, object, subject=None):
-    assert self.running
-    entry = ActivityEntry()
-    entry.actor = actor
-    entry.verb = verb
-    entry.object_id = object.id
-    entry.object_class = object.__class__.__name__
-    if subject:
-      entry.subject_id = subject.id
-      entry.subject_class = subject.__class__.__name__
-
-    db.session.add(entry)
-
-  @staticmethod
-  def entries_for_actor(actor, limit=50):
-    return ActivityEntry.query.filter(ActivityEntry.actor_id == actor.id).limit(limit).all()
diff --git a/abilian/services/activity/service.py b/abilian/services/activity/service.py
new file mode 100644
index 00000000..0dfb4a0a
--- /dev/null
+++ b/abilian/services/activity/service.py
@@ -0,0 +1,45 @@
+from abilian.core.extensions import db
+from abilian.core.signals import activity
+
+from .models import ActivityEntry
+
+
+__all__ = ['ActivityService']
+
+
+class ActivityService(object):
+
+  def __init__(self, app=None):
+    self.running = False
+    if app:
+      self.init_app(app)
+
+  def init_app(self, app):
+    self.app = app
+
+  def start(self):
+    assert not self.running
+    activity.connect(self.log_activity)
+    self.running = True
+
+  def stop(self):
+    assert self.running
+    activity.disconnect(self.log_activity)
+    self.running = False
+
+  def log_activity(self, sender, actor, verb, object, subject=None):
+    assert self.running
+    entry = ActivityEntry()
+    entry.actor = actor
+    entry.verb = verb
+    entry.object_id = object.id
+    entry.object_class = object.__class__.__name__
+    if subject:
+      entry.subject_id = subject.id
+      entry.subject_class = subject.__class__.__name__
+
+    db.session.add(entry)
+
+  @staticmethod
+  def entries_for_actor(actor, limit=50):
+    return ActivityEntry.query.filter(ActivityEntry.actor_id == actor.id).limit(limit).all()
diff --git a/abilian/services/activity/tests.py b/abilian/services/activity/tests.py
new file mode 100644
index 00000000..ba7086d3
--- /dev/null
+++ b/abilian/services/activity/tests.py
@@ -0,0 +1,37 @@
+from abilian.core.entities import Entity
+from abilian.core.extensions import db
+from abilian.core.subjects import User
+from abilian.testing import BaseTestCase
+
+from .service import ActivityService
+
+
+class Message1(Entity):
+  pass
+
+class ActivityTestCase(BaseTestCase):
+
+  def setUp(self):
+    BaseTestCase.setUp(self)
+    self.activity_service = ActivityService()
+    self.activity_service.start()
+
+  def test(self):
+    service = self.activity_service
+    user = User(email=u'test@example.com')
+    message = Message1()
+
+    db.session.add(user)
+    db.session.add(message)
+    db.session.flush()
+
+    service.log_activity(None, user, "post", message)
+    db.session.flush()
+
+    entries = service.entries_for_actor(user, 10)
+    self.assertEquals(len(entries), 1)
+    entry = entries[0]
+    self.assertEquals(entry.actor, user)
+    self.assertEquals(entry.object, message)
+
+
diff --git a/abilian/services/tagging/service.py b/abilian/services/tagging/service.py
index b8a247f2..08866a44 100644
--- a/abilian/services/tagging/service.py
+++ b/abilian/services/tagging/service.py
@@ -1,6 +1,10 @@
+"""
+
+"""
 
 class Taggable(object):
-  """Mixin trait for taggable objects.
+  """
+  Mixin trait for taggable objects.
 
   Currently not used.
   """
@@ -8,7 +12,8 @@ class Taggable(object):
 
 
 class TagService(object):
-  """The tag service.
+  """
+  The tag service.
   """
 
   def tag(self, object, term, user=None):
@@ -22,7 +27,9 @@ def untag(self, object, term, user=None):
     """
 
   def get_objects_tagged_with(self, term):
-    """Returns a list of objects tagged with a given term."""
+    """Returns a list of objects tagged with a given term.
+    """
 
   def get_tags_applied_on(self, object):
-    """Return a list of tags applied on a given document."""
+    """Returns a list of tags applied on a given document.
+    """
diff --git a/abilian/testing/__init__.py b/abilian/testing/__init__.py
index d0d63115..9e6b0e4f 100644
--- a/abilian/testing/__init__.py
+++ b/abilian/testing/__init__.py
@@ -11,6 +11,7 @@ class TestConfig(object):
   SQLALCHEMY_DATABASE_URI = "sqlite://"
   SQLALCHEMY_ECHO = False
   TESTING = True
+  SECRET = ""
 
 
 class BaseTestCase(TestCase):