Add travis testing support for python 3.8 (#477)

* Add travis testing support for python 3.8

* Use Xenial for all

* Simplify matrix

* Consistent indents

* Add py38 to tox and update contributing guide for how to use pyenv

* Fix travis spec to allow 3.8-dev to fail and tox should pass 90% coverage for full suite

.gitignore

@@ -10,6 +10,8 @@ coverage.xml
 htmlcov/
 *.egg-info/
 pytestdebug.log
+pip-wheel-metadata/
+.python-version
 
 fixtures/
 /docs/_build

.travis.yml

@@ -1,3 +1,4 @@
+dist: xenial
 language: python
 before_install: openssl version
 env:
@@ -13,55 +14,31 @@ env:
     - TOX_SUFFIX="aiohttp"
 matrix:
   include:
+    # Only run lint on a single 3.x
     - env: TOX_SUFFIX="lint"
-      python: 3.7
-      dist: xenial
-    - env: TOX_SUFFIX="requests"
-      python: 3.7
-      dist: xenial
-    - env: TOX_SUFFIX="httplib2"
-      python: 3.7
-      dist: xenial
-    - env: TOX_SUFFIX="boto3"
-      python: 3.7
-      dist: xenial
-    - env: TOX_SUFFIX="urllib3"
-      python: 3.7
-      dist: xenial
-    - env: TOX_SUFFIX="tornado4"
-      python: 3.7
-      dist: xenial
-    - env: TOX_SUFFIX="aiohttp"
-      python: 3.7
-      dist: xenial
+      python: "3.7"
   allow_failures:
     - env: TOX_SUFFIX="aiohttp"
       python: "pypy3"
+    - python: "3.8-dev"
   exclude:
-    # Only run lint on a single 3.x
-    - env: TOX_SUFFIX="lint"
-      python: 2.7
-    - env: TOX_SUFFIX="lint"
-      python: 3.5
-    - env: TOX_SUFFIX="lint"
-      python: pypy
-    - env: TOX_SUFFIX="lint"
-      python: "pypy3"
     # Exclude aiohttp support
     - env: TOX_SUFFIX="aiohttp"
-      python: 2.7
+      python: "2.7"
     - env: TOX_SUFFIX="aiohttp"
-      python: pypy
+      python: "pypy"
 python:
-- 2.7
-- 3.5
-- 3.6
-- pypy
-- "pypy3"
+  - "2.7"
+  - "3.5"
+  - "3.6"
+  - "3.7"
+  - "3.8-dev"
+  - "pypy"
+  - "pypy3"
 install:
-- pip install tox-travis codecov
-- if [[ $TOX_SUFFIX != 'lint' ]]; then python setup.py install ; fi
+  - pip install tox-travis codecov
+  - if [[ $TOX_SUFFIX != 'lint' ]]; then python setup.py install ; fi
 script:
-- tox -e "${TOX_SUFFIX}"
+  - tox -e "${TOX_SUFFIX}"
 after_success:
   - codecov

docs/contributing.rst

@@ -27,6 +27,38 @@ for how to set this up. I have marked the boto tests as optional in
 Travis so you don't have to worry about them failing if you submit a
 pull request.
 
+Using PyEnv with VCR's test suite
+---------------------------------
+
+PyEnv is a tool for managing multiple installation of python on your system.
+See the full documentation at their `github <https://github.com/pyenv/pyenv>` 
+but we are also going to use `tox-pyenv <https://pypi.org/project/tox-pyenv/>` 
+in this example::
+
+    git clone https://github.com/pyenv/pyenv ~/.pyenv
+
+    # Add ~/.pyenv/bin to your PATH
+    export PATH="$PATH:~/.pyenv/bin"
+
+    # Setup shim paths
+    eval "$(pyenv init -)"
+
+    # Setup your local system tox tooling
+    pip install tox tox-pyenv
+
+    # Install supported versions (at time of writing), this does not activate them
+    pyenv install 2.7.10 3.5.7 3.6.9 3.7.4 3.8-dev pypy2.6-7.1.1 pypy3.6-7.1.1
+
+    # This activates them
+    pyenv local 2.7.10 3.5.7 3.6.9 3.7.4 3.8-dev pypy2.6-7.1.1 pypy3.6-7.1.1
+
+    # Run the whole test suite
+    tox
+
+    # Run the whole test suite or just part of it
+    tox -e lint
+    tox -e py37-requests
+
 
 Troubleshooting on MacOSX
 -------------------------

tox.ini

@@ -1,6 +1,11 @@
 [tox]
 skip_missing_interpreters=true
-envlist = cov-clean,{py27,py35,py36,py37,pypy}-{lint,requests,httplib2,urllib3,tornado4,boto3},{py35,py36,py37}-{aiohttp},cov-report
+envlist = 
+  cov-clean,
+  lint,
+  {py27,py35,py36,py37,py38,pypy,pypy3}-{requests,httplib2,urllib3,tornado4,boto3},
+  {py35,py36,py37,py38}-{aiohttp},
+  cov-report
 
 
 # Coverage environment tasks: cov-clean and cov-report
@@ -15,7 +20,7 @@ deps = coverage
 skip_install=true
 commands = 
   coverage html
-  coverage report --fail-under=80
+  coverage report --fail-under=90
 
 [testenv:lint]
 skipsdist = True