Properly test on Python 3.7 and 3.8-dev.

Author: kdeldycke

.travis.yml

@@ -1,22 +1,35 @@
 # After changing this file, check it on: https://lint.travis-ci.org/
 language: python
-sudo: false
+sudo: required
 
 # Python targets, as defined by https://github.com/travis-ci/travis-build/blob
 # /master/spec/build/script/python_spec.rb and https://github.com/travis-ci
 # /travis-build/blob/master/lib/travis/build/script/python.rb
-python:
-  # Standard release https://docs.travis-ci.com/user/languages
-  # /python#choosing-python-versions-to-test-against
-  - "2.7"
-  - "3.4"
-  - "3.5"
-  - "3.6"
-  - "3.7-dev"  # a.k.a "nightly"
+# Standard release https://docs.travis-ci.com/user/languages
+# /python#choosing-python-versions-to-test-against
+matrix:
 
-  # PyPy2.7: https://doc.pypy.org/en/latest
-  # /index-of-release-notes.html#cpython-2-7-compatible-versions
-  - pypy-5.4
+  # Explicitely set all python version to a distribution as some are not
+  # supported by default distribution.
+  include:
+    - python: "2.7"
+      dist: trusty
+    - python: "3.4"
+      dist: trusty
+    - python: "3.5"
+      dist: trusty
+    - python: "3.6"
+      dist: trusty
+    # We need to switch to Xenial starting with Python 3.7. See:
+    # https://github.com/travis-ci/travis-ci/issues/9069#issuecomment-425720905
+    - python: "3.7"
+      dist: xenial
+    - python: "3.8-dev"
+      dist: xenial
+    # PyPy2.7: https://doc.pypy.org/en/latest
+    # /index-of-release-notes.html#cpython-2-7-compatible-versions
+    - python: "pypy-5.4"
+      dist: trusty
 
 before_install:
   # Check default Python version installed.

setup.py

@@ -150,6 +150,8 @@ def long_description():
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Software Development :: Libraries :: Python Modules',