Merge pull request #7047 from tk0miya/test_with_nightly_python_again

Test with nightly python again (refs: #7001)

.travis.yml

@@ -24,7 +24,7 @@ matrix:
       env:
         - TOXENV=du15
         - PYTEST_ADDOPTS="--cov ./ --cov-append --cov-config setup.cfg"
-    - python: '3.8'
+    - python: 'nightly'
       env:
         - TOXENV=du16
     - python: '3.6'

tox.ini

@@ -1,16 +1,17 @@
 [tox]
 minversion = 2.4.0
-envlist = docs,flake8,mypy,coverage,py{35,36,37,38},du{12,13,14,15}
+envlist = docs,flake8,mypy,coverage,py{35,36,37,38,39},du{12,13,14,15}
 
 [testenv]
 usedevelop = True
 passenv =
     https_proxy http_proxy no_proxy PERL PERL5LIB PYTEST_ADDOPTS EPUBCHECK_PATH
 description =
-    py{35,36,37,38}: Run unit tests against {envname}.
+    py{35,36,37,38,39}: Run unit tests against {envname}.
     du{12,13,14}: Run unit tests with the given version of docutils.
 deps =
     coverage < 5.0  # refs: https://github.com/sphinx-doc/sphinx/pull/6924
+    git+https://github.com/html5lib/html5lib-python ; python_version >= "3.9"  # refs: https://github.com/html5lib/html5lib-python/issues/419
     du12: docutils==0.12
     du13: docutils==0.13.1
     du14: docutils==0.14