Add tox for testing

Author: VMRuiz

requirements.txt

@@ -0,0 +1,12 @@
+[tox]
+envlist = min,py39,py310,py311
+skip_missing_interpreters = True
+
+[testenv]
+deps =
+    pytest
+    pytest-cov
+commands = pytest --cov=src --cov-report=term {posargs:tests}
+
+[testenv:min]
+basepython = python3.8