Update Travis CI matrix (chibisov#245)

* Migrate testing matrix to use tox-travis

This migrates the existing versions of Python and Django that are tested in Travis to be replicated within the Tox matrix. This also changes Travis CI to run tests using tox-travis, which will automatically run all of the test envionments matching a specific Python version.

* Test on Django 2.1

It's been released for a few months now, so we may as well test on it.

* Test on DRF 3.8 and 3.9

Previously this was only being tested on the latest version of DRF, instead of being tested on each minor version.

* Test on Python 3.7

* Fix Tox config misspelling

* Remove ancient requirements file

* Add Python 3.7 to Tox config

* Apparently we use Django-Nose in tests?

These tests are so damn old...

* Tests require the old mock module

We should be able to swap this out with the new Mock module provided by Python 3, but that's a lot of effort that I am not in the mood to put in.

* Revert removal of that old requirements file

I've made a mistake.

* Stop testing on Django 2.1

These test failure are known, I'll let them be handled in the other pull request.

* Added back Django Guardian to testing requirements

.travis.yml

@@ -1,20 +1,16 @@
 language: python
 cache: pip
+dist: xenial
+sudo: false
 
 python:
-  - "3.6"
-  - "3.5"
-  - "3.4"
-
-env:
-  - TOXENV=django.1.11
-  - TOXENV=django.2.0
-
-matrix:
-  fast_finish: true
+  - 3.4
+  - 3.5
+  - 3.6
+  - 3.7
 
 install:
-  - pip install tox
+  - pip install tox tox-travis
 
 script:
   - tox

tests_app/requirements.txt

@@ -2,4 +2,4 @@ nose
 django-nose
 django-filter==1.1
 mock
-ipdb
+ipdb

tox.ini

@@ -1,31 +1,20 @@
 [tox]
 envlist =
-    django.2.0
-    django.1.11
-
+    py34-django{111,20}-drf{38,39}
+    py35-django{111,20}-drf{38,39}
+    py36-django{111,20}-drf{38,39}
+    py37-django{111,20}-drf{38,39}
 
 [testenv]
 deps=
     -rtests_app/requirements.txt
+    django-guardian>=1.4.4
+    drf38: djangorestframework>=3.8.1,<3.9
+    drf39: djangorestframework>=3.9.0,<3.10
+    django111: Django>=1.11,<2.0
+    django20: Django>=2.0,<2.1
+    django21: Django>=2.1,<2.2
 setenv =
     PYTHONPATH = {toxinidir}:{toxinidir}/tests_app
 commands=
-    {envbindir}/django-admin.py test --settings=settings {posargs}
-
-
-[testenv:django.1.11]
-deps=
-    {[testenv]deps}
-    Django>=1.11,<2.0
-    djangorestframework>=3.8.1
-    django-guardian>=1.4.4
-
-
-[testenv:django.2.0]
-deps=
-    {[testenv]deps}
-    Django>=2.0,<2.1
-    djangorestframework>=3.8.1
-    django-guardian>=1.4.4
-
-
+    {envbindir}/django-admin.py test --settings=settings {posargs}