more improved testing

Jenkinsfile

@@ -58,7 +58,9 @@ pipeline {
 
       stage('update repo structure') {
         steps {
-          sh '''rm -Rf REPOSTRUCTURE.md
+          sh '''if [ test -f REPOSTRUCTURE.md ]; then
+                rm -Rf REPOSTRUCTURE.md
+                fi
                 echo "$(tree --dirsfirst --charset=ascii .)" > REPOSTRUCTURE.md'''
         }
       }
@@ -183,10 +185,12 @@ Changelog of Git Changelog.
 
       stage('check for UTF-8 files') {
         steps {
-          sh '''if [ ! -d test ]; then
-                mkdir test
+          sh '''if [ ! -d tests ]; then
+                mkdir tests
                 fi
+                if [ -f tests/UTF_Files ]; then
                 rm -Rf tests/UTF_Files
+                fi
                 echo "$(find . -type f -exec file {} \\;)" > FileList
                 echo  "$(grep -v ASCII FileList | grep -v git)" > tests/UTF_Files'''
         }