Add unit test for negative ignore patterns in import command

tests-ng/compare-negative-ignore.sh

@@ -50,7 +50,7 @@ cur=$(dirname "$(${rl} "${0}")")
 
 # dotdrop path can be pass as argument
 ddpath="${cur}/../"
-[ "${1}" != "" ] && ddpath="${1}"
+[ -n "${1}" ] && ddpath="${1}"
 [ ! -d ${ddpath} ] && echo "ddpath \"${ddpath}\" is not a directory" && exit 1
 
 export PYTHONPATH="${ddpath}:${PYTHONPATH}"
@@ -129,4 +129,4 @@ set -e
 rm -rf ${basedir} ${tmpd}
 
 echo "OK"
-exit 0
+exit 0