Set up pytest

setup.cfg

@@ -5,3 +5,6 @@ universal=1
 source-dir = docs
 build-dir  = docs/build
 all_files  = 1
+
+[aliases]
+test=pytest

setup.py

@@ -4,6 +4,8 @@ setup(name='Mastodon.py',
       version='1.0.6',
       description='Python wrapper for the Mastodon API',
       packages=['mastodon'],
+      setup_requires=['pytest-runner'],
+      tests_require=['pytest'],
       install_requires=['requests', 'dateutils'],
       url='https://github.com/halcy/Mastodon.py',
       author='Lorenz Diener',