diff --git a/test-requirements.txt b/test-requirements.txt
new file mode 100644
index 000000000..471df3031
--- /dev/null
+++ b/test-requirements.txt
@@ -0,0 +1,3 @@
+coverage
+pytest
+defcon==0.3.5
diff --git a/tox.ini b/tox.ini
index f3efd16ad..b9cab5d37 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,8 +3,7 @@ envlist = py27, py36, htmlcov
 
 [testenv]
 deps =
-    pytest
-    coverage
+    -rtest-requirements.txt
     -rrequirements.txt
 commands =
     coverage run --parallel-mode -m pytest {posargs}