diff --git a/tests/grib_sub_hourly.sh b/tests/grib_sub_hourly.sh
index d3c031ee8..ffb0a17f7 100755
--- a/tests/grib_sub_hourly.sh
+++ b/tests/grib_sub_hourly.sh
@@ -490,6 +490,15 @@ grib_check_key_equals $temp '-p startStep' '16m'
 grib_check_key_equals $temp '-p indicatorOfUnitOfTimeRange' '0'
 grib_check_key_equals $temp '-p forecastTime' '16'
 
+
+export ECCODES_GRIB_SHOW_HOUR_STEPUNIT=1
+cat >$tempFilt<<EOF
+    assert ( step is "6h" );
+EOF
+cat $tempFilt
+${tools_dir}/grib_filter $tempFilt $data_dir/constant_field.grib2
+unset ECCODES_GRIB_SHOW_HOUR_STEPUNIT
+
 # Bad stepUnits
 set +e
 ${tools_dir}/grib_set -s stepUnits=190 $sample_g2 $temp > $tempText 2>&1