travis,appveyor: also test setup.py install

.appveyor.yml

@@ -25,5 +25,7 @@ build_script:
   - set CFLAGS=-std=c90 -Wall -Wno-long-long -Werror
   - cd %APPVEYOR_BUILD_FOLDER%
   - bash -xlc "%PYTHON% setup.py test"
+  - bash -xlc "%PYTHON% setup.py sdist"
+  - bash -xlc "%PYTHON% -m pip install dist/*"
 
 deploy: off

.travis.yml

@@ -49,4 +49,6 @@ install:
 script:
   - python setup.py test
   - python -m flake8 .
+  - python setup.py sdist
+  - python -m pip install "$(eval 'echo dist/*')"
   - if [ "$TRAVIS_PYTHON_VERSION" != "3.3" ]; then python -m sphinx -W -a -E -b html -n docs docs/_build; fi