Adds tox configuration to test with multiple python versions.
diff --git a/run_tests.py b/run_tests.py
new file mode 100644
index 0000000..e0f2490
--- /dev/null
+++ b/run_tests.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import os
+import sys
+import unittest2 as unittest
+
+current_path = os.path.abspath(os.path.dirname(__file__))
+tests_path = os.path.join(current_path, 'tests')
+sys.path[0:0] = [
+    current_path,
+    tests_path,
+]
+
+all_tests = [f[:-3] for f in os.listdir(tests_path)
+             if f.startswith('test_') and f.endswith(".py")]
+
+def get_suite(tests):
+    tests = sorted(tests)
+    suite = unittest.TestSuite()
+    loader = unittest.TestLoader()
+    for test in tests:
+        suite.addTest(loader.loadTestsFromName(test))
+    return suite
+
+if __name__ == '__main__':
+    """
+    To run all tests:
+        $ python run_tests.py
+    To run a single test:
+        $ python run_tests.py app
+    To run a couple of tests:
+        $ python run_tests.py app config sessions
+    To run code coverage:
+        $ coverage run run_tests.py
+        $ coverage report -m
+    """
+    tests = sys.argv[1:]
+    if not tests:
+        tests = all_tests
+    tests = ['%s' % t for t in tests]
+    suite = get_suite(tests)
+    unittest.TextTestRunner(verbosity=1).run(suite)