Before:
  Save g:ale_c_parse_makefile
  let g:ale_c_parse_makefile = 0

  call ale#assert#SetUpLinterTest('c', 'gcc')

  let b:command_tail = ' -S -x c'
  \   . ' -o ' . (has('win32') ? 'nul': '/dev/null')
  \   . ' -iquote ' . ale#Escape(getcwd())
  \   . ' -std=c11 -Wall -'

After:
  call ale#assert#TearDownLinterTest()

  unlet! b:command_tail

Execute(The executable should be configurable):
  AssertLinter 'gcc', [ale#Escape('gcc') . b:command_tail]

  let b:ale_c_gcc_executable = 'foobar'

  AssertLinter 'foobar', [ale#Escape('foobar') . b:command_tail]