Before:
  runtime ale_linters/ruby/rubocop.vim

Execute(Executable should default to rubocop):
  AssertEqual
  \ 'rubocop --format emacs --force-exclusion  --stdin ''dummy.py''',
  \ ale_linters#ruby#rubocop#GetCommand(bufnr(''))

Execute(Should be able to set a custom executable):
  let g:ale_ruby_rubocop_executable = 'bin/rubocop'
  AssertEqual
  \ 'bin/rubocop --format emacs --force-exclusion  --stdin ''dummy.py''',
  \ ale_linters#ruby#rubocop#GetCommand(bufnr(''))

Execute(Custom executables should not be escaped):
  let g:ale_ruby_rubocop_executable = 'bundle exec rubocop'
  AssertEqual
  \ 'bundle exec rubocop --format emacs --force-exclusion  --stdin ''dummy.py''',
  \ ale_linters#ruby#rubocop#GetCommand(bufnr(''))

Execute(Executable callback should return the first token of the executable):
  let g:ale_ruby_rubocop_executable = 'bundle exec rubocop'
  AssertEqual
  \ 'bundle',
  \ ale_linters#ruby#rubocop#GetExecutable(bufnr(''))
  let g:ale_ruby_rubocop_executable = 'bin/rubocop'
  AssertEqual
  \ 'bin/rubocop',
  \ ale_linters#ruby#rubocop#GetExecutable(bufnr(''))