drop support for Python 2.7 and 3.5

tox.ini

@@ -1,16 +1,14 @@
 [tox]
 envlist =
-    py{38,37,36,35,27,py3,py}
+    py{38,37,36,py3}
     py38-{simplejson,devel,lowest}
+    style
     docs
-    coverage
 skip_missing_interpreters = true
 
 [testenv]
-passenv = LANG
 deps =
     pytest
-    coverage
     greenlet
     blinker
     python-dotenv
@@ -29,18 +27,10 @@ deps =
     simplejson: simplejson
 
 commands =
-    # the examples need to be installed to test successfully
     pip install -q -e examples/tutorial[test]
     pip install -q -e examples/javascript[test]
 
-    # pytest-cov doesn't seem to play nice with -p
-    coverage run -p -m pytest --tb=short -Werror {posargs:tests examples}
-
-[testenv:nightly]
-# courtesy Python nightly test, don't fail the build in CI
-ignore_outcome = true
-commands =
-    coverage run -p -m pytest --tb=short -Werror --junitxml=test-results.xml tests
+    pytest --tb=short --basetemp={envtmpdir} {posargs:tests examples}
 
 [testenv:style]
 deps = pre-commit
@@ -48,22 +38,5 @@ skip_install = true
 commands = pre-commit run --all-files --show-diff-on-failure
 
 [testenv:docs]
-deps =
-    -r docs/requirements.txt
+deps = -r docs/requirements.txt
 commands = sphinx-build -W -b html -d {envtmpdir}/doctrees docs {envtmpdir}/html
-
-[testenv:coverage]
-deps = coverage
-skip_install = true
-commands =
-    coverage combine
-    coverage html
-    coverage report
-
-[testenv:coverage-ci]
-deps = coverage
-skip_install = true
-commands =
-    coverage combine
-    coverage xml
-    coverage report