Folding example from Learn Vimscript the Hard Way not working?

Question

I'm reading Learn Vimscript the Hard Way - Chapter 18, which is also about folds.

I'm surprised to see that copying the sample code

" Vimscript file settings ---------------------- {{{
augroup filetype_vim
    autocmd!
    autocmd FileType vim setlocal foldmethod=marker
augroup END
" }}}

into my ~/.vimrc, saving it, closing it, reopening it, putting the cursor on one of those lines, and pressing za doesn't have any effect.

Putting it more simply, if I don't do do anything of what I've written above, but I just paste the following in my ~/.vimrc

" Folding ---------------------- {{{
" this should be foldable
" }}}

then run :set foldmethod=marker and then I hit za on the middle line, nothing happens.

What can I be doing wrong?

Answer 1

Commenting the ~/.vimrc and uncommenting it bit by bit I found out that the reason for the folding not working was that I was setting foldminlines to a value higher than the number of lines of the fold I was trying to close.