diff --git a/tests/constraints.txt b/tests/constraints.txt
index 3bc30de15..e59e68b3f 100644
--- a/tests/constraints.txt
+++ b/tests/constraints.txt
@@ -1 +1,2 @@
 Twisted!=18.4.0
+lxml!=4.2.2
\ No newline at end of file
diff --git a/tox.ini b/tox.ini
index c2fa9af28..82348eb24 100644
--- a/tox.ini
+++ b/tox.ini
@@ -67,6 +67,7 @@ commands =
 [testenv:py34]
 basepython = python3.4
 deps =
+    -ctests/constraints.txt
     -rrequirements-py3.txt
     # Extras
     Pillow