diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 *.orig
 __pycache__
+*.egg-info
 *.trace
 build
 qtcreator-build
diff --git a/dev-tools/python/dev-requirements.txt b/dev-tools/python/dev-requirements.txt
new file mode 100644
--- /dev/null
+++ b/dev-tools/python/dev-requirements.txt
@@ -0,0 +1,6 @@
+flake8==3.6.0
+pytest==4.0.2
+PyQt5==5.11.3
+PyQt5-sip==4.19.13
+
+-e dev-tools/python/krita-mock
diff --git a/dev-tools/python/krita-mock/setup.py b/dev-tools/python/krita-mock/setup.py
new file mode 100644
--- /dev/null
+++ b/dev-tools/python/krita-mock/setup.py
@@ -0,0 +1,8 @@
+from setuptools import setup, find_namespace_packages
+
+setup(
+    name="krita",
+    version="0.1",
+    packages=find_namespace_packages('src'),
+    package_dir={'': 'src'},
+)
diff --git a/dev-tools/python/krita-mock/src/krita/__init__.py b/dev-tools/python/krita-mock/src/krita/__init__.py
new file mode 100644
--- /dev/null
+++ b/dev-tools/python/krita-mock/src/krita/__init__.py
@@ -0,0 +1,31 @@
+"""This is a mock krita module for Python unit tests.
+
+This module returns a mock object for any attribute name and thus
+prevents any errors surrounding the krita module in unit tests. This
+makes it possible to write unit tests for Krita-independent code
+units.
+
+Caveats:
+
+Will only work with proper imports:
+
+ import krita
+ krita.Krita.instance() # no-op on a mock object
+
+Not with wildcard imports:
+
+ from krita import *
+ Krita.instance() # error
+
+(Wildcard imports should be avoided anyway.)
+
+"""
+
+import builtins
+import sys
+from unittest.mock import MagicMock
+
+
+sys.modules['krita'] = MagicMock()
+
+builtins.i18n = lambda s: s
diff --git a/plugins/python/CMakeLists.txt b/plugins/python/CMakeLists.txt
--- a/plugins/python/CMakeLists.txt
+++ b/plugins/python/CMakeLists.txt
@@ -57,6 +57,7 @@
                 PATTERN "*.csv"
                 PATTERN "*.html"
                 PATTERN "__pycache__*" EXCLUDE
+                PATTERN "tests*" EXCLUDE
            )
         # TODO Is there any way to form a long PATTERN options string
         # and use it in a single install() call?
@@ -68,6 +69,7 @@
                 FILES_MATCHING
                     PATTERN "${_pattern}"
                     PATTERN "__pycache__*" EXCLUDE
+		    PATTERN "tests*" EXCLUDE
               )
         endforeach()
     else()
diff --git a/plugins/python/plugin_importer/tests/__init__.py b/plugins/python/plugin_importer/tests/__init__.py
new file mode 100644
diff --git a/plugins/python/plugin_importer/tests/test_plugin_importer.py b/plugins/python/plugin_importer/tests/test_plugin_importer.py
new file mode 100644
--- /dev/null
+++ b/plugins/python/plugin_importer/tests/test_plugin_importer.py
@@ -0,0 +1,37 @@
+import os
+import pytest
+from tempfile import TemporaryDirectory
+from unittest import TestCase
+
+
+from .. plugin_importer import PluginImporter, PluginReadError
+
+
+class PluginImporterTestCase(TestCase):
+
+    def setUp(self):
+        self.resources_dir = TemporaryDirectory()
+        self.plugin_dir = TemporaryDirectory()
+
+    def tearDown(self):
+        self.resources_dir.cleanup()
+        self.plugin_dir.cleanup()
+
+    @property
+    def zip_filename(self):
+        return os.path.join(
+            self.resources_dir.name, 'plugin.zip')
+
+    def test_zipfile_doesnt_exist(self):
+        with pytest.raises(PluginReadError):
+            PluginImporter(self.zip_filename,
+                           self.resources_dir.name,
+                           lambda x: True)
+
+    def test_zipfile_not_a_zip(self):
+        with open(self.zip_filename, 'w') as f:
+            f.write('foo')
+        with pytest.raises(PluginReadError):
+            PluginImporter(self.zip_filename,
+                           self.resources_dir.name,
+                           lambda x: True)
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,4 @@
+# Setting for various Python tools (code checks, unit tests etc)
+
+[flake8]
+builtins = i18n,Scripter,Application,Krita