diff --git a/backend/app/models.py b/backend/app/models.py
index 9cace57..142d734 100644
--- a/backend/app/models.py
+++ b/backend/app/models.py
@@ -89,7 +89,7 @@ class User(UserMixin, db.Model):
                 .join(Post.author.of_type(Author))
                 .join(Author.followers.of_type(Follower), isouter=True)
                 .where(sa.or_(
-                    Follower.id == self.id
+                    Follower.id == self.id,
                     Author.id == self.id
                 ))
                 .group_by(Post)
diff --git a/backend/config.py b/backend/config.py
index d05ad60..e1efeb1 100644
--- a/backend/config.py
+++ b/backend/config.py
@@ -5,8 +5,8 @@ basedir = os.path.abspath(os.path.dirname(__file__))
 
 class Config:
     SECRET_KEY = os.environ.get('FLASK_SECRET_KEY') or 'flasksk'
-    #SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(basedir, 'zapp.db')
-    SQLALCHEMY_DATABASE_URI = 'mariadb+mariadbconnector://flasku:' + os.environ.get('MYSQL_PASSWORD') + '@db:3306/flask'
+    SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(basedir, 'zapp.db')
+    #SQLALCHEMY_DATABASE_URI = 'mariadb+mariadbconnector://flasku:' + os.environ.get('MYSQL_PASSWORD') + '@db:3306/flask'
 
     #MAIL_SERVER = 'pmb'
     MAIL_SERVER = ''
diff --git a/backend/tests.py b/backend/tests.py
index 1b31bb1..305ed03 100644
--- a/backend/tests.py
+++ b/backend/tests.py
@@ -2,4 +2,94 @@ import os
 os.environ['DATABASE_URL'] = 'sqlite://'
 
 from datetime import datetime, timezone, timedelta
+import unittest
+from app import app, db
+from app.models import User, Post
+
+
+class UserModelCase(unittest.TestCase):
+    def setUp(self):
+        self.app_context = app.app_context()
+        self.app_context.push()
+        db.create_all()
+
+    def tearDown(self):
+        db.session.remove()
+        db.drop_all()
+        self.app_context.pop()
+
+    def test_password_hashing(self):
+        u = User(username='susan', email='susan@example.com')
+        u.set_password('cat')
+        self.assertFalse(u.check_password('dog'))
+        self.assertTrue(u.check_password('cat'))
+
+    def test_follow(self):
+        u1 = User(username='john', email='john@example.com')
+        u2 = User(username='susan', email='susan@example.com')
+        db.session.add(u1)
+        db.session.add(u2)
+        db.session.commit()
+        following = db.session.scalars(u1.following.select()).all()
+        followers = db.session.scalars(u2.followers.select()).all()
+        self.assertEqual(following, [])
+        self.assertEqual(followers, [])
+
+        u1.follow(u2)
+        db.session.commit()
+        self.assertTrue(u1.is_following(u2))
+        self.assertEqual(u1.following_count(), 1)
+        self.assertEqual(u2.followers_count(), 1)
+        u1_following = db.session.scalars(u1.following.select()).all()
+        u2_followers = db.session.scalars(u2.followers.select()).all()
+        self.assertEqual(u1_following[0].username, 'susan')
+        self.assertEqual(u2_followers[0].username, 'john')
+
+        u1.unfollow(u2)
+        db.session.commit()
+        self.assertFalse(u1.is_following(u2))
+        self.assertEqual(u1.following_count(), 0)
+        self.assertEqual(u2.followers_count(), 0)
+
+    def test_follow_posts(self):
+        # create four users
+        u1 = User(username='john', email='john@example.com')
+        u2 = User(username='susan', email='susan@example.com')
+        u3 = User(username='mary', email='mary@example.com')
+        u4 = User(username='david', email='david@example.com')
+        db.session.add_all([u1, u2, u3, u4])
+
+        # create four posts
+        now = datetime.now(timezone.utc)
+        p1 = Post(body="post from john", author=u1,
+                  timestamp=now + timedelta(seconds=1))
+        p2 = Post(body="post from susan", author=u2,
+                  timestamp=now + timedelta(seconds=4))
+        p3 = Post(body="post from mary", author=u3,
+                  timestamp=now + timedelta(seconds=3))
+        p4 = Post(body="post from david", author=u4,
+                  timestamp=now + timedelta(seconds=2))
+        db.session.add_all([p1, p2, p3, p4])
+        db.session.commit()
+
+        # setup the followers
+        u1.follow(u2)  # john follows susan
+        u1.follow(u4)  # john follows david
+        u2.follow(u3)  # susan follows mary
+        u3.follow(u4)  # mary follows david
+        db.session.commit()
+
+        # check the following posts of each user
+        f1 = db.session.scalars(u1.following_posts()).all()
+        f2 = db.session.scalars(u2.following_posts()).all()
+        f3 = db.session.scalars(u3.following_posts()).all()
+        f4 = db.session.scalars(u4.following_posts()).all()
+        self.assertEqual(f1, [p2, p4, p1])
+        self.assertEqual(f2, [p2, p3])
+        self.assertEqual(f3, [p3, p4])
+        self.assertEqual(f4, [p4])
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)