diff --git a/bookwyrm/models/base_model.py b/bookwyrm/models/base_model.py
index 91724e62..121b5f75 100644
--- a/bookwyrm/models/base_model.py
+++ b/bookwyrm/models/base_model.py
@@ -96,7 +96,7 @@ class ActivitypubMixin:
         ''' returns the object wrapped in a Create activity '''
         activity_object = self.to_activity()
 
-        signer = pkcs1_15.new(RSA.import_key(user.private_key))
+        signer = pkcs1_15.new(RSA.import_key(user.key_pair.private_key))
         content = activity_object['content']
         signed_message = signer.sign(SHA256.new(content.encode('utf8')))
         create_id = self.remote_id + '/activity'
diff --git a/bookwyrm/models/status.py b/bookwyrm/models/status.py
index 6fa9f995..a2b873bb 100644
--- a/bookwyrm/models/status.py
+++ b/bookwyrm/models/status.py
@@ -44,11 +44,6 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
     )
     objects = InheritanceManager()
 
-    @property
-    def ap_replies(self):
-        ''' structured replies block '''
-        return self.to_replies()
-
     activity_serializer = activitypub.Note
     serialize_reverse_fields = ['attachments']
 
diff --git a/bookwyrm/tests/models/test_base_model.py b/bookwyrm/tests/models/test_base_model.py
index 7e383a46..9568ae6a 100644
--- a/bookwyrm/tests/models/test_base_model.py
+++ b/bookwyrm/tests/models/test_base_model.py
@@ -1,14 +1,15 @@
 ''' testing models '''
+from collections import namedtuple
 from django.test import TestCase
 
 from bookwyrm import models
-from bookwyrm.models.base_model import BookWyrmModel
+from bookwyrm.models import base_model
+from bookwyrm.models.base_model import ActivitypubMixin
 from bookwyrm.settings import DOMAIN
 
-
 class BaseModel(TestCase):
     def test_remote_id(self):
-        instance = BookWyrmModel()
+        instance = base_model.BookWyrmModel()
         instance.id = 1
         expected = instance.get_remote_id()
         self.assertEqual(expected, 'https://%s/bookwyrmmodel/1' % DOMAIN)
@@ -16,10 +17,55 @@ class BaseModel(TestCase):
     def test_remote_id_with_user(self):
         user = models.User.objects.create_user(
             'mouse', 'mouse@mouse.com', 'mouseword', local=True)
-        instance = BookWyrmModel()
+        instance = base_model.BookWyrmModel()
         instance.user = user
         instance.id = 1
         expected = instance.get_remote_id()
         self.assertEqual(
             expected,
             'https://%s/user/mouse/bookwyrmmodel/1' % DOMAIN)
+
+    def test_execute_after_save(self):
+        ''' this function sets remote ids after creation '''
+        # using Work because it BookWrymModel is abstract and this requires save
+        # Work is a relatively not-fancy model.
+        instance = models.Work.objects.create(title='work title')
+        instance.remote_id = None
+        base_model.execute_after_save(None, instance, True)
+        self.assertEqual(
+            instance.remote_id,
+            'https://%s/book/%d' % (DOMAIN, instance.id)
+        )
+
+        # shouldn't set remote_id if it's not created
+        instance.remote_id = None
+        base_model.execute_after_save(None, instance, False)
+        self.assertIsNone(instance.remote_id)
+
+    def test_to_create_activity(self):
+        user = models.User.objects.create_user(
+            'mouse', 'mouse@mouse.com', 'mouseword', local=True)
+
+        object_activity = {
+            'to': 'to field', 'cc': 'cc field',
+            'content': 'hi',
+            'published': '2020-12-04T17:52:22.623807+00:00',
+        }
+        MockSelf = namedtuple('Self', ('remote_id', 'to_activity'))
+        mock_self = MockSelf(
+            'https://example.com/status/1',
+            lambda *args: object_activity
+        )
+        activity = ActivitypubMixin.to_create_activity(mock_self, user)
+        self.assertEqual(
+            activity['id'],
+            'https://example.com/status/1/activity'
+        )
+        self.assertEqual(activity['actor'], user.remote_id)
+        self.assertEqual(activity['to'], 'to field')
+        self.assertEqual(activity['cc'], 'cc field')
+        self.assertEqual(activity['object'], object_activity)
+        self.assertEqual(
+            activity['signature'].creator,
+            '%s#main-key' % user.remote_id
+        )