Add testing for Python 3.9

Author: nicoddemus

.github/workflows/main.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ["3.5", "3.6", "3.7", "3.8"]
+        python: ["3.5", "3.6", "3.7", "3.8", "3.9"]
         os: [ubuntu-latest, windows-latest]
         include:
           - python: "3.5"
@@ -21,6 +21,8 @@ jobs:
             tox_env: "py37"
           - python: "3.8"
             tox_env: "py38"
+          - python: "3.9"
+            tox_env: "py39"
 
     steps:
     - uses: actions/checkout@v1

setup.py

@@ -34,6 +34,7 @@
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "Topic :: Software Development :: Testing",
     ],
 )

tox.ini

@@ -1,11 +1,11 @@
 [tox]
-envlist = py{35,36,37,38}, linting
+envlist = py{35,36,37,38,39},linting
 
 [testenv]
 deps =
     pytest-xdist
 commands =
-    pytest tests
+    pytest -n1 tests
 
 [testenv:linting]
 skipsdist = True