Merge ~peter-sabaini/charm-sudo-pair:fix-tests into ~sudo-pair-charmers/charm-sudo-pair:master

[Peter Sabaini]

[Diko Parvanov (dparv)]

lgtm

review: Approve

diff --git a/tests/functional/requirements.txt b/tests/functional/requirements.txt
index 6c6cdc6..b9815c2 100644
--- a/tests/functional/requirements.txt
+++ b/tests/functional/requirements.txt
@@ -1,6 +1,6 @@
 juju
 requests
-pytest==4.0.2
+pytest
 pytest-asyncio
 mock
 flake8
diff --git a/tox.ini b/tox.ini
index 7d3565b..562d0ba 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,7 @@ envlist = unit, functional, func_xenial
 skip_missing_interpreters = True
 
 [testenv]
-basepython = python3.6
+basepython = python3
 setenv =
   PYTHONPATH = .