cat > test-expr-count.vim << EOF
    function! DelNthSpace()
        echom v:count1
        return virtcol('.').'|'
    endfunction
    nnoremap <expr> s DelNthSpace()
EOF
echo $':echom "Here"\nsshsshss:redir! >messages\n:messages\n:redir END\n:qa!\n' | vim -u NONE -c 'so test-expr-count.vim' -c 'normal a...' -c 'normal ssssss'