tox: Use pytest as test runner

tox.ini

@@ -4,12 +4,18 @@ envlist = py27, flake8
 [testenv]
 sitepackages = true
 deps =
-    coverage
     mock
-    nose
     mopidy==dev
+    pytest
+    pytest-cov
+    pytest-xdist
 install_command = pip install --allow-unverified=mopidy --pre {opts} {packages}
-commands = nosetests -v --with-xunit --xunit-file=xunit-{envname}.xml --with-coverage --cover-package=mopidy_touchscreen
+commands =
+    py.test \
+        --basetemp={envtmpdir} \
+        --junit-xml=xunit-{envname}.xml \
+        --cov=mopidy_touchpanel --cov-report=term-missing \
+        {posargs}
 
 [testenv:flake8]
 deps =