diff --git a/Makefile b/Makefile
index ba4ec367..f8f87d8b 100644
--- a/Makefile
+++ b/Makefile
@@ -29,7 +29,7 @@ remove-install-stamp:
 update: remove-install-stamp install
 
 serve: install
-	cd budget; $(PYTHON) run.py
+	$(PYTHON) -m budget.manage runserver
 
 test: $(DEV_STAMP)
 	$(VENV)/bin/tox
diff --git a/budget/api.py b/budget/api.py
index 4b991bdf..7ce6a34f 100644
--- a/budget/api.py
+++ b/budget/api.py
@@ -2,9 +2,9 @@
 from flask import Blueprint, request
 from flask_rest import RESTResource, need_auth
 
-from models import db, Project, Person, Bill
-from forms import (ProjectForm, EditProjectForm, MemberForm,
-                   get_billform_for)
+from .models import db, Project, Person, Bill
+from .forms import (ProjectForm, EditProjectForm, MemberForm,
+                    get_billform_for)
 
 
 api = Blueprint("api", __name__, url_prefix="/api")
diff --git a/budget/forms.py b/budget/forms.py
index 06df7430..bd7fc5b5 100644
--- a/budget/forms.py
+++ b/budget/forms.py
@@ -7,10 +7,11 @@ from flask_babel import lazy_gettext as _
 from flask import request
 
 from wtforms.widgets import html_params
-from models import Project, Person
 from datetime import datetime
 from jinja2 import Markup
-from utils import slugify
+
+from .models import Project, Person
+from .utils import slugify
 
 def get_billform_for(project, set_default=True, **kwargs):
     """Return an instance of BillForm configured for a particular project.
diff --git a/budget/manage.py b/budget/manage.py
index f717fed5..0a662840 100755
--- a/budget/manage.py
+++ b/budget/manage.py
@@ -1,12 +1,12 @@
 #!/usr/bin/env python
 
+from getpass import getpass
 from flask_script import Manager, Command
 from flask_migrate import Migrate, MigrateCommand
 from werkzeug.security import generate_password_hash
 
-from run import app
-from models import db
-from getpass import getpass
+from .run import app
+from .models import db
 
 
 class GeneratePasswordHash(Command):
@@ -20,8 +20,12 @@ migrate = Migrate(app, db)
 
 manager = Manager(app)
 manager.add_command('db', MigrateCommand)
-manager.add_command('generate_password_hash', GeneratePasswordHash)
+manager.add_command('generate_password_hash', GeneratePasswordHash)   
+
+
+def main():
+    manager.run()
 
 
 if __name__ == '__main__':
-    manager.run()
+    main()
diff --git a/budget/run.py b/budget/run.py
index 7fe4e245..5e65c905 100644
--- a/budget/run.py
+++ b/budget/run.py
@@ -7,12 +7,12 @@ from flask_babel import Babel
 from flask_migrate import Migrate, upgrade, stamp
 from raven.contrib.flask import Sentry
 
-from web import main, db, mail
-from api import api
-from utils import PrefixedWSGI
-from utils import minimal_round
+from .web import main, db, mail
+from .api import api
+from .utils import PrefixedWSGI
+from .utils import minimal_round
 
-import default_settings
+from . import default_settings
 
 app = Flask(__name__, instance_path='/etc/ihatemoney', instance_relative_config=True)
 
diff --git a/budget/tests/tests.py b/budget/tests/tests.py
index 16aaae9f..386920f5 100644
--- a/budget/tests/tests.py
+++ b/budget/tests/tests.py
@@ -17,9 +17,9 @@ from flask import session
 if 'IHATEMONEY_SETTINGS_FILE_PATH' in os.environ:
     del os.environ['IHATEMONEY_SETTINGS_FILE_PATH']
 
-import run
-import models
-import utils
+from .. import run
+from .. import models
+from .. import utils
 
 __HERE__ = os.path.dirname(os.path.abspath(__file__))
 
diff --git a/budget/web.py b/budget/web.py
index f4961cbf..ba771247 100644
--- a/budget/web.py
+++ b/budget/web.py
@@ -9,8 +9,10 @@ some shortcuts to make your life better when coding (see `pull_project`
 and `add_project_id` for a quick overview)
 """
 
-from flask import Blueprint, current_app, flash, g, redirect, \
-    render_template, request, session, url_for, send_file
+from flask import (
+    Blueprint, current_app, flash, g, redirect, render_template, request,
+    session, url_for, send_file
+)
 from flask_mail import Mail, Message
 from flask_babel import get_locale, gettext as _
 from werkzeug.security import generate_password_hash, \
@@ -20,12 +22,13 @@ import werkzeug
 from sqlalchemy import orm
 from functools import wraps
 
-# local modules
-from models import db, Project, Person, Bill
-from forms import AdminAuthenticationForm, AuthenticationForm, EditProjectForm, \
-    InviteForm, MemberForm, PasswordReminder, ProjectForm, get_billform_for, \
+from .models import db, Project, Person, Bill
+from .forms import (
+    AdminAuthenticationForm, AuthenticationForm, EditProjectForm,
+    InviteForm, MemberForm, PasswordReminder, ProjectForm, get_billform_for,
     ExportForm
-from utils import Redirect303, list_of_dicts2json, list_of_dicts2csv
+)
+from .utils import Redirect303, list_of_dicts2json, list_of_dicts2csv
 
 main = Blueprint("main", __name__)
 mail = Mail()
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 0bbb0aa0..8795457f 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,2 +1,3 @@
 zest.releaser
 tox
+pytest
diff --git a/tox.ini b/tox.ini
index 23f54f49..b918bdbe 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,7 +6,7 @@ skip_missing_interpreters = True
 
 commands =
     python --version
-    python -m unittest discover -s budget
+    py.test budget/tests/tests.py
 deps =
     -rdev-requirements.txt
     -rrequirements.txt