<NME> test-requirements.txt
<BEF> factory-boy>=2.4
testfixtures==4.7.0
httmock==1.2.5
tox
asynctest

<MSG> Merge pull request #947 from tonioo/refactor/documentation

Refactor/documentation
<DFF> @@ -1,3 +1,4 @@
 factory-boy>=2.4
 testfixtures==4.7.0
 httmock==1.2.5
+tox

Merge pull request #947 from tonioo/refactor/documentation