diff --git a/script/ci/before_install.sh b/script/ci/before_install.sh
index c5236b071..6b0fae571 100755
--- a/script/ci/before_install.sh
+++ b/script/ci/before_install.sh
@@ -4,3 +4,6 @@
 envdir="$(readlink -e $(dirname $0))/../env"
 . "$envdir/ruby_env"
 . "$envdir/ensure_right_rubygems"
+
+# install selenium prerelease
+gem install selenium-webdriver --pre