add checks for the presence of tabs and trailing whitespaces

Scripts/developer_scripts/test_merge_of_branch

@@ -162,6 +162,24 @@ if [ -n "${txt_not_utf8}" ]; then
   exit 1
 fi
 
+#check no file contains tab characters
+echo '.. Checking if tab character is used...'
+file_with_tabs=$(git ls-files --stage | egrep '\.txt|\.h$|\.cpp|\.hpp' | awk '{print $4}' | xargs grep -P -l '\t')
+if [ -n "${file_with_tabs}" ]; then
+  echo "The following files have tabs:"
+  echo ${file_with_tabs}
+  exit 1
+fi
+
+#check no file contains trailing whitespaces characters
+echo '.. Look for trailing whitespaces...'
+files_with_trailingws=$(git ls-files --stage | egrep '\.txt|\.h$|\.cpp|\.hpp' | awk '{print $4}' | xargs grep -P -l '\s+$')
+if [ -n "${files_with_trailingws}" ]; then
+  echo "The following files have trailing whitespaces:"
+  echo ${files_with_trailingws}
+  exit 1
+fi
+
 #check all headers in documentation actually exist
 echo '.. Checking if all documentation headers exist'
 not_existing_headers=$(bash ./Scripts/developer_scripts/check_headers.sh $PWD)