Before:
  Save g:ale_c_clang_executable
  Save g:ale_c_clang_options

  unlet! g:ale_c_clang_executable
  unlet! b:ale_c_clang_executable
  unlet! g:ale_c_clang_options
  unlet! b:ale_c_clang_options

  runtime ale_linters/c/clang.vim

  let b:command_tail = ' -S -x c -fsyntax-only -iquote'
  \   . ' ' . ale#Escape(getcwd())
  \   . ' -std=c11 -Wall -'

After:
  Restore
  unlet! b:command_tail
  unlet! b:ale_c_clang_executable
  unlet! b:ale_c_clang_options
  call ale#linter#Reset()

Execute(The executable should be configurable):
  AssertEqual 'clang', ale_linters#c#clang#GetExecutable(bufnr(''))

  let b:ale_c_clang_executable = 'foobar'

  AssertEqual 'foobar', ale_linters#c#clang#GetExecutable(bufnr(''))

Execute(The executable should be used in the command):
  AssertEqual
  \ ale#Escape('clang') . b:command_tail,
  \ ale_linters#c#clang#GetCommand(bufnr(''), [])

  let b:ale_c_clang_executable = 'foobar'

  AssertEqual
  \ ale#Escape('foobar') . b:command_tail,
  \ ale_linters#c#clang#GetCommand(bufnr(''), [])