diff --git a/requirements/development.in b/requirements/development.in
--- a/requirements/development.in
+++ b/requirements/development.in
@@ -32,4 +32,7 @@ mock~=1.3.0
 sphinx~=1.6.0
 
 # Used for handling of timezones.
-pytz
\ No newline at end of file
+pytz
+
+# Used for running functional tests.
+selenium~=3.8.0
\ No newline at end of file