introduce tox support

.gitignore

@@ -8,4 +8,5 @@ __pycache__/
 *.pyo
 .travis.pub
 .pytest_cache/
+.tox/
 keyfile.toml

tests/test_htmlparser.py

@@ -3,7 +3,17 @@
 
 import pytest
 
-pytestmark = [pytest.mark.asyncio, pytest.mark.needs_net]
+lxml_available = True
+try:
+  import lxml
+except ImportError:
+  lxml_available = False
+
+pytestmark = [
+  pytest.mark.asyncio,
+  pytest.mark.needs_net,
+  pytest.mark.skipif(not lxml_available, reason="needs lxml"),
+]
 
 async def test_xpath_ok(get_version):
     assert await get_version("unifiedremote", {

tox.ini

@@ -0,0 +1,16 @@
+[tox]
+isolated_build = True
+# you may find `tox --skip-missing-interpreters=true` helpful.
+envlist = py3{7,8,9,10}
+
+[testenv]
+usedevelop = false
+deps =
+  pytest
+  pytest-asyncio
+  pytest-httpbin
+  flaky
+extras =
+  htmlparser
+passenv = KEYFILE
+commands = pytest -r fEs {posargs}