Add dummy test with tox

tests/test_dummy.py

+def func(x):
+    return x + 1
+
+
+def test_answer():
+    assert func(41) == 42

tox.ini

+[tox]
+envlist = py36
+
+[testenv]
+deps =  
+    -rrequirements.txt
+    pytest
+
+commands = pytest