diff --git a/script/includes.sh b/script/includes.sh
new file mode 100644
index 0000000000..1b0519f940
--- /dev/null
+++ b/script/includes.sh
@@ -0,0 +1,6 @@
+function exit_unless_master_merged {
+    if [[ `git branch -a --merged $BUILDKITE_BRANCH` != *origin/master* ]]; then
+	echo "This branch does not have the current master merged. Please merge master and push again."
+	exit 1
+    fi
+}
diff --git a/script/run_tests.sh b/script/run_tests.sh
index 461ca4ecd8..616d454e5d 100755
--- a/script/run_tests.sh
+++ b/script/run_tests.sh
@@ -3,11 +3,15 @@
 set -e
 
 echo "--- Loading environment"
+source ./script/includes.sh
 source /var/lib/jenkins/.rvm/environments/ruby-1.9.3-p392
 if [ ! -f config/application.yml ]; then
     ln -s application.yml.example config/application.yml
 fi
 
+echo "--- Verifying branch is based on current master"
+exit_unless_master_merged
+
 echo "--- Bundling"
 bundle install