testvimrc.vim

" install vim-pulg
if has('vim_starting')
  set rtp+=~/.vim/plugged/vim-plug
  if !isdirectory(expand('~/.vim/plugged/vim-plug'))
    echo 'install vim-plug...'
    call mkdir(expand('~/.vim/plugged/vim-plug'), 'p')
    call system('git clone https://github.com/junegunn/vim-plug.git ' . expand('~/.vim/plugged/vim-plug/autoload'))
  end
endif
" setup
call plug#begin('~/.vim/plugged')
Plug 'prabirshrestha/async.vim'
Plug 'prabirshrestha/vim-lsp'
Plug 'prabirshrestha/asyncomplete.vim'
Plug 'prabirshrestha/asyncomplete-lsp.vim'
Plug 'mattn/vim-lsp-settings'
call plug#end()
" plugin setting - lsp
augroup LspMappings
  au!
  au FileType vim,python call s:lsp_common_mappings()
augroup END
function! s:lsp_common_mappings() abort
  setlocal omnifunc=lsp#complete
  nmap <buffer> K <Plug>(lsp-hover)
  nmap <buffer> <silent> [g <Plug>(lsp-previous-diagnostic)
  nmap <buffer> <silent> ]g <Plug>(lsp-next-diagnostic)
  nmap <buffer> gd <Plug>(lsp-definition)
endfunction
inoremap <expr> <C-y> pumvisible() ? asyncomplete#close_popup() : "\<C-y>"
inoremap <expr> <C-e> pumvisible() ? asyncomplete#cancel_popup() : "\<C-e>"

Invoke
gvim -N -u testvimrc.vim