commit https://github.com/vim/vim/commit/c8ce615299b4d8c1b2e6cf83496f48cd497d8a37 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Aug 7 13:48:20 2016 +0200 patch 7.4.2174 Problem: Adding duplicate flags to 'whichwrap' leaves commas behind. Solution: Also remove the commas. (Naruhiko Nishino)

" Test for joining lines.

func Test_join_with_count()
  new
  call setline(1, ['one', 'two', 'three', 'four'])
  normal J
  call assert_equal('one two', getline(1))
  %del
  call setline(1, ['one', 'two', 'three', 'four'])
  normal 10J
  call assert_equal('one two three four', getline(1))
  quit!
endfunc