diff --git a/tools/run_tests/build_python.sh b/tools/run_tests/build_python.sh
index 365abb4d8638a5b845a260d574ab5c3c23340d7c..f120fc7ed6905ecc896d6dfcf2d7eaa82b9a9124 100755
--- a/tools/run_tests/build_python.sh
+++ b/tools/run_tests/build_python.sh
@@ -46,4 +46,5 @@ tox --notest
 
 $ROOT/.tox/py27/bin/python $ROOT/setup.py build
 $ROOT/.tox/py27/bin/python $ROOT/setup.py build_py
+$ROOT/.tox/py27/bin/python $ROOT/setup.py build_ext --inplace
 $ROOT/.tox/py27/bin/python $ROOT/setup.py gather --test