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

<MSG> SMTP authentication backend.

see #989

<DFF> @@ -1,4 +1,5 @@
 factory-boy>=2.4
-testfixtures==4.7.0
+mock==2.0.0
 httmock==1.2.5
+testfixtures==4.7.0
 tox

SMTP authentication backend.