Make tox configuration less redundant

Author: Cito

docs/testing.rst

@@ -39,9 +39,10 @@ To test only the example servlets in the default context::
 
     python -m unittest discover -p TestExamples.py -vs Tests.TestEndToEnd
 
-You can also use tox_ as a test runner. The Webware source package already contains a suitable tox.ini configuration file for running the unit tests with all supported Python versions, and also running a few additional code quality checks.
+You can also use tox_ as a test runner. The Webware source package already contains a suitable tox.ini configuration file for running the unit tests with all supported Python versions, and also running a few additional code quality checks. Make sure to use current versions of _tox and _virtualenv when running the tests.
 
 .. _tox: https://tox.readthedocs.io/en/latest/
+.. _virtualenv: https://virtualenv.readthedocs.io/en/latest/
 
 Testing Webware applications
 ----------------------------

setup.py

@@ -14,14 +14,14 @@
     'Pygments>=2,<3', 'waitress>=1.4.2,<2', 'hupper>=1.9,<2', 'WebTest>=2,<3'
 ]
 requireDocs = [
-    'Sphinx>=2.2,<3', 'sphinx_rtd_theme>=0.4'
+    'Sphinx>=2.3,<3', 'sphinx_rtd_theme>=0.4'
 ]
 requireExamples = [
-    'Pygments>=2,<3', 'Pillow>=6,<7', 'dominate>=2,<3', 'yattag>=1,<2'
+    'Pygments>=2,<3', 'Pillow>=6,<8', 'dominate>=2,<3', 'yattag>=1,<2'
 ]
 requireTest = [
     'psutil>=5,<6', 'flake8>=3.7,<4', 'pylint>=2.4,<3', 'tox>=3.14,<4',
-    'pywin32>=227,<300;platform_system=="Windows"'
+    'pywin32>=227,<300;sys_platform=="win32"'
 ] + requireDev + requireDocs + requireExamples
 
 

tox.ini

@@ -16,7 +16,7 @@ commands =
 [testenv:docs]
 basepython = python3.8
 deps =
-    sphinx>=2.2,<3
+    sphinx>=2.3,<3
     sphinx_rtd_theme>=0.4
 commands =
     sphinx-build -b html -nEW docs docs/_build/html
@@ -28,18 +28,9 @@ commands =
     check-manifest -v
 
 [testenv]
-platform =
-    windows: win32
 setenv =
     PYTHONPATH = {toxinidir}/webware
-deps =
-    waitress>=1.4.2,<2
-    psutil>=5,<6
-    WebTest>=2,<3
-    Pygments>=2,<3
-    Pillow>=6,<7
-    dominate>=2,<3
-    yattag>=1,<2
-    pywin32>=227,<300;platform_system=="Windows"
+extras =
+    test
 commands =
     python -m unittest discover -fv -p Test*.py