diff --git a/test.sh b/test.sh
index 88f2ccdb..a52251c0 100755
--- a/test.sh
+++ b/test.sh
@@ -7,7 +7,7 @@ echo "Testing command line interface with cram"
 COVERAGE=1 cram --verbose $@  test_cmdline/*.cram
 cram_exit=$?
 echo "Executing unit tests with pytest"
-PYTHONPATH=. pytest --cov=bloscpack test
+PYTHONPATH=. pytest --cov=bloscpack --cov-append test
 pytest_exit=$?
 if [ $cram_exit -gt 0 ] || [ $pytest_exit -gt 0 ] ; then
     echo "some tests failed"