Before:
  call ale#assert#SetUpLinterTest('llvm', 'llc')

  function! AssertHasPrefix(str, prefix) abort
    let msg = printf("'%s' is expected to be prefixed with '%s'", a:str, a:prefix)
    AssertEqual stridx(a:str, a:prefix), 0, msg
  endfunction

After:
  delfunction AssertHasPrefix

  call ale#assert#TearDownLinterTest()

Execute(The llc command should be customizable):
  AssertLinter 'llc',
  \ ale#Escape('llc') . ' -filetype=null -o=' . g:ale#util#nul_file

  let g:ale_llvm_llc_executable = 'llc-5.0'

  AssertLinter 'llc-5.0',
  \ ale#Escape('llc-5.0') . ' -filetype=null -o=' . g:ale#util#nul_file
