diff --git a/run_tests.sh b/run_tests.sh
index 9ac346f..abb74bf 100644
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -2,7 +2,9 @@
 
 set -e
 set -x
-#export PYTHONPATH=${PYTHONPATH:.}
+default_pythonpath=$PYTHONPATH:.
+export PYTHONPATH=${default_pythonpath:-.}
+>&2 echo using pythonpath $PYTHONPATH
 for f in `ls tests/*.py`; do
 	python $f
 done