travis-ci: simplify test setup with tox and coverage uploading

.travis.yml

@@ -1,13 +1,19 @@
 language: python
 python:
-    - 2.7
-    - 3.3
-    - 3.4
+  - 2.7
+  - 3.3
+  - 3.4
+  - nightly
+matrix:
+  fast_finish: true
+  allow_failures:
+    - python: nightly
 sudo: false
-install: pip install 'tox<2' 'coveralls>0.5'
-script: tox -e py${TRAVIS_PYTHON_VERSION/\./}
+cache:
+  directories:
+    - $HOME/.cache/pip
+install: pip install 'tox<2' 'coveralls>=0.5'
+script: tox -e travis
 after_success:
-    # upload coverage data to coveralls.io
-    - pushd .tox/py${TRAVIS_PYTHON_VERSION/\./}/lib/python*/site-packages
-    - coveralls
-    - popd
+  # upload coverage data
+  - coveralls

tox.ini

@@ -16,4 +16,12 @@ deps =
 commands =
 	pip install "{toxinidir}"
 	cp "{toxinidir}/.coveragerc" "{envsitepackagesdir}"
-	py.test {posargs:-n 4 --cov pychroot "{toxinidir}/test"}
+	py.test {posargs:-n 4 --cov-report html --cov pychroot "{toxinidir}/test"}
+
+# stub for travis-ci
+[testenv:travis]
+commands =
+	pip install "{toxinidir}"
+	cp "{toxinidir}/.coveragerc" "{envsitepackagesdir}"
+	py.test {posargs:-n 4 --cov-report xml --cov pychroot "{toxinidir}/test"}
+	cp coverage.xml "{toxinidir}"