Fix implicit dependencies

Make sure that all direct dependencies are listed in requirements.txt .

Change-Id: If99e774aab6944d3b0529edce94d9efbe73923a3
diff --git a/requirements.txt b/requirements.txt
index 17f694d..6a74e48 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,3 +3,5 @@
 oslo.utils>=3.37.0 # Apache-2.0
 tempest>=17.1.0 # Apache-2.0
 gabbi>=2.7.0 # Apache-2.0
+requests>=2.14.2 # Apache-2.0
+testtools>=2.2.0 # MIT