Streamline travis-ci build.

Instead of running a DEPS=false version of every test, just run one
test environment per version and use a separate virtualenv for basic
tests in the DEPS=false case.

.travis.yml

@@ -10,24 +10,23 @@ python:
     - nightly
     - pypy3
 
-env:
-    - DEPS=true
-    - DEPS=false
-
 install:
-    - if [[ $TRAVIS_PYTHON_VERSION == 2* && $DEPS == true ]]; then travis_retry pip install futures mock Monotime trollius; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == 'pypy' && $DEPS == true ]]; then travis_retry pip install futures mock; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 2* ]]; then travis_retry pip install futures mock Monotime trollius; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 'pypy' ]]; then travis_retry pip install futures mock; fi
     # TODO(bdarnell): pycares tests are currently disabled on travis due to ipv6 issues.
-    #- if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* && $DEPS == true ]]; then travis_retry pip install pycares; fi
-    - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* && $DEPS == true ]]; then travis_retry pip install pycurl; fi
+    #- if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then travis_retry pip install pycares; fi
+    - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then travis_retry pip install pycurl; fi
     # Twisted runs on 2.x and 3.3+, but is flaky on pypy.
-    - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* && $DEPS == true ]]; then travis_retry pip install Twisted; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == '2.7' && $DEPS == true ]]; then travis_retry pip install sphinx sphinx_rtd_theme; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == '3.5' && $DEPS == true ]]; then travis_retry pip install sphinx sphinx_rtd_theme; fi
+    - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then travis_retry pip install Twisted; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == '2.7' || $TRAVIS_PYTHON_VERSION == '3.5' ]]; then travis_retry pip install sphinx sphinx_rtd_theme; fi
     # On travis the extension should always be built
     - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then export TORNADO_EXTENSION=1; fi
     - travis_retry python setup.py install
     - travis_retry pip install codecov
+    # Create a separate no-dependencies virtualenv to make sure all imports
+    # of optional-dependencies are guarded.
+    - virtualenv ./nodeps
+    - ./nodeps/bin/python setup.py install
     - curl-config --version; pip freeze
 
 script:
@@ -53,25 +52,25 @@ script:
     - LANG=C python $TARGET
     - LANG=en_US.utf-8 python $TARGET
     - if [[ $TRAVIS_PYTHON_VERSION == 3* ]]; then python -bb $TARGET; fi
-    - if [[ $TRAVIS_PYTHON_VERSION != pypy* && $DEPS == true ]]; then python $TARGET --resolver=tornado.netutil.ThreadedResolver; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == 2* && $DEPS == true ]]; then python $TARGET --httpclient=tornado.curl_httpclient.CurlAsyncHTTPClient; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == 2* && $DEPS == true ]]; then python $TARGET --ioloop_time_monotonic; fi
-    - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* && $DEPS == true ]]; then python $TARGET --ioloop=tornado.platform.twisted.TwistedIOLoop; fi
+    - if [[ $TRAVIS_PYTHON_VERSION != pypy* ]]; then python $TARGET --resolver=tornado.netutil.ThreadedResolver; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 2* ]]; then python $TARGET --httpclient=tornado.curl_httpclient.CurlAsyncHTTPClient; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 2* ]]; then python $TARGET --ioloop_time_monotonic; fi
+    - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then python $TARGET --ioloop=tornado.platform.twisted.TwistedIOLoop; fi
     - if [[ $TRAVIS_PYTHON_VERSION == 3.4 || $TRAVIS_PYTHON_VERSION == 3.5 ]]; then python $TARGET --ioloop=tornado.platform.asyncio.AsyncIOLoop; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == 2* && $DEPS == true ]]; then python $TARGET --ioloop=tornado.platform.asyncio.AsyncIOLoop; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == 2* && $DEPS == true ]]; then python $TARGET --resolver=tornado.platform.twisted.TwistedResolver; fi
-    #- if [[ $TRAVIS_PYTHON_VERSION != pypy* && $DEPS == true ]]; then python $TARGET --resolver=tornado.platform.caresresolver.CaresResolver; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 2* ]]; then python $TARGET --ioloop=tornado.platform.asyncio.AsyncIOLoop; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == 2* ]]; then python $TARGET --resolver=tornado.platform.twisted.TwistedResolver; fi
+    #- if [[ $TRAVIS_PYTHON_VERSION != pypy* ]]; then python $TARGET --resolver=tornado.platform.caresresolver.CaresResolver; fi
     - if [[ $TRAVIS_PYTHON_VERSION == 3* ]]; then python $TARGET --ioloop_time_monotonic; fi
+    - ../nodeps/bin/python -m tornado.test.runtests
     # make coverage reports for Codecov to find
     - if [[ $TRAVIS_PYTHON_VERSION != nightly ]]; then coverage xml; fi
     - export TORNADO_EXTENSION=0
-    - if [[ $TRAVIS_PYTHON_VERSION == '3.5' && $DEPS == true ]]; then cd ../docs && mkdir sphinx-out && sphinx-build -E -n -W -b html . sphinx-out; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == '2.7' && $DEPS == true ]]; then cd ../docs && mkdir sphinx-doctest-out && sphinx-build -E -n -b doctest . sphinx-out; fi
-    - if [[ $TRAVIS_PYTHON_VERSION == '3.5' && $DEPS == true ]]; then cd ../docs && mkdir sphinx-doctest-out && sphinx-build -E -n -b doctest . sphinx-out; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == '3.5' ]]; then cd ../docs && mkdir sphinx-out && sphinx-build -E -n -W -b html . sphinx-out; fi
+    - if [[ $TRAVIS_PYTHON_VERSION == '2.7' || $TRAVIS_PYTHON_VERSION == '3.5' ]]; then cd ../docs && mkdir sphinx-doctest-out && sphinx-build -E -n -b doctest . sphinx-out; fi
 
 after_success:
     # call codecov from project root
-    - if [[ $TRAVIS_PYTHON_VERSION != nightly ]]; then cd ../ && codecov -e DEPS; fi
+    - if [[ $TRAVIS_PYTHON_VERSION != nightly ]]; then cd ../ && codecov; fi
 
 # This reportedly works around an issue downloading packages from pypi on
 # travis.  Consider removing this after the underlying issue is fixed.