diff --git a/tox.ini b/tox.ini
index 849f581c..88a8d0a1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,6 +4,7 @@ skipsdist = true
 
 [testenv]
 deps=
+    aniso8601
     pytest>=2.7.2
     graphql-core>=1.1
     promise>=2.0
@@ -11,10 +12,12 @@ deps=
     six
     blinker
     singledispatch
+    snapshottest
     mock
     pytz
     iso8601
     pytest-benchmark
+    pytest-mock
 setenv =
      PYTHONPATH = .:{envdir}
 commands=