adjust travis-ci config to reflect new tox settings

.travis.yml

@@ -1,5 +1,6 @@
 language: python
 sudo: false
+<<<<<<< HEAD
 python:
     - 2.7
     - 3.4
@@ -13,17 +14,55 @@ matrix:
     exclude:
         - env: ENVIRON=isort,flake8,docs
         - env: ENVIRON=py27-datetime,py36-datetime
+=======
+
+matrix:
+>>>>>>> adjust travis-ci config to reflect new tox settings
     include:
+        - python: "2.7"
+          env: TOXENV=docs,lint-py2
         - python: "3.6"
-          env: ENVIRON=py36-datetime,isort,flake8,docs
+          env: TOXENV=docs,lint-py3
+        - python: "2.7"
+          env: TOXENV=py27
         - python: "2.7"
+          env: TOXENV=py27-rp3
+        - python: "2.7"
+<<<<<<< HEAD
           env: ENVIRON=py27-datetime
+=======
+          env: TOXENV=py27-datetime
+        - python: "3.4"
+          env: TOXENV=py34
+        - python: "3.5"
+          env: TOXENV=py35
+        - python: "3.6"
+          env: TOXENV=py36
+        - python: "3.6"
+          env: TOXENV=py36-datetime
+        - python: "3.7-dev"
+          env: TOXENV=py37
+        - python: "pypy"
+          env: TOXENV=pypy
+        - python: "pypy3"
+          env: TOXENV=pypy
+    allow_failures:
+        - python: "pypy"
+          env: TOXENV=pypy
+        - python: "pypy3"
+          env: TOXENV=pypy
+
+>>>>>>> adjust travis-ci config to reflect new tox settings
 install:
-    - pip install tox coveralls coverage
+    - travis_retry pip install -U pip setuptools
+    - travis_retry pip install -U -c constraints.txt tox coveralls coverage
+
 script:
-    - tox -e $ENVIRON
+    - travis_retry tox
+
 after_success:
     - coverage combine
     - coveralls
+
 notifications:
     email: false

tox.ini

@@ -6,7 +6,9 @@ envlist =
     py35,
     py36,
     py36-datetime,
+    py37,
     pypy,
+    pypy3,
     docs,
     lint-py2,
     lint-py3,