diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,4 @@
 dist/
 *.egg-info
 version.txt
+.tox/
diff --git a/requirements-test.txt b/requirements-test.txt
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -1 +1,3 @@
-nose
+pytest
+dulwich >= 0.18.7
+swh.loader.git
diff --git a/swh/vault/cookers/base.py b/swh/vault/cookers/base.py
--- a/swh/vault/cookers/base.py
+++ b/swh/vault/cookers/base.py
@@ -90,7 +90,7 @@
 
         Override this in the cooker implementation.
         """
-        raise NotImplemented
+        raise NotImplementedError
 
     @abc.abstractmethod
     def prepare_bundle(self):
@@ -98,7 +98,7 @@
 
         Override this with the cooker implementation.
         """
-        raise NotImplemented
+        raise NotImplementedError
 
     def write(self, chunk):
         self.fileobj.write(chunk)
@@ -118,7 +118,7 @@
         except PolicyError as e:
             self.backend.set_status(self.obj_type, self.obj_id, 'failed')
             self.backend.set_progress(self.obj_type, self.obj_id, str(e))
-        except Exception as e:
+        except Exception:
             self.backend.set_status(self.obj_type, self.obj_id, 'failed')
             self.backend.set_progress(
                 self.obj_type, self.obj_id,
diff --git a/swh/vault/tests/test_cookers.py b/swh/vault/tests/test_cookers.py
--- a/swh/vault/tests/test_cookers.py
+++ b/swh/vault/tests/test_cookers.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2017  The Software Heritage developers
+# Copyright (C) 2017-2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -9,6 +9,7 @@
 import io
 import os
 import pathlib
+import pytest
 import subprocess
 import tarfile
 import tempfile
@@ -100,6 +101,7 @@
         self.git_shell(*args, stdout=None)
 
 
+@pytest.mark.config_issue
 class BaseTestCookers(VaultTestFixture):
     """Base class of cookers unit tests"""
     def setUp(self):
diff --git a/tox.ini b/tox.ini
new file mode 100644
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,17 @@
+[tox]
+envlist=flake8,py3
+
+[testenv:py3]
+deps =
+  .[testing]
+  pytest-cov
+  pifpaf
+commands =
+  pifpaf run postgresql -- pytest --cov=swh --cov-branch {posargs} -m 'not config_issue'
+
+[testenv:flake8]
+skip_install = true
+deps =
+  flake8
+commands =
+  {envpython} -m flake8