tox: create a new py3-sys environment

Create a new py3-sys environment that is dedicated to being the "leaky"
testenv, the one that uses system python packages.
Let `py3` and `py39` and so on work like typical tox environments
that use virtualenvs without site packages. These can control
the dependencies. The py3-sys target will be the one for testing
with the system's libs & site packages.

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

tox.ini

@@ -1,6 +1,6 @@
 
 [tox]
-envlist = formatting, {py3,py39}-mypy, py3, py39, schemacheck
+envlist = formatting, {py3,py39}-mypy, py3, py39, schemacheck, py3-sys
 isolated_build = True
 
 [testenv]
@@ -20,11 +20,14 @@ deps =
     mypy
     types-setuptools
     types-pyyaml
+    types-jsonschema>=4.10
     {[testenv]deps}
 commands =
     mypy sambacc tests
 
-[testenv:py3]
+[testenv:py3-sys]
+# py3-sys -- more like sisyphus, am I right?
+#
 # In order to run tests that rely on "system level" packages (samba,
 # xattr, etc.), and not have a lot of test skips, we have to enable the
 # sitepackages option. However when it is enabled and you already have a tool
@@ -34,9 +37,13 @@ commands =
 # section.
 sitepackages = True
 deps =
+    pytest
+    pytest-cov
+    dnspython
     inotify_simple
     pyxattr
-    {[testenv]deps}
+allowlist_externals =
+    /usr/bin/py.test
 
 [testenv:formatting]
 deps =