Before:
  call ale#assert#SetUpLinterTest('nix', 'deadnix')

After:
  call ale#assert#TearDownLinterTest()

Execute(The deadnix command should be correct):
  AssertLinter 'deadnix', ale#Escape('deadnix') . ' -o json -- %t'

Execute(Additional deadnix options should be configurable):
  let g:ale_nix_deadnix_options = '--foobar'

  AssertLinter 'deadnix',
  \ ale#Escape('deadnix') . ' -o json --foobar -- %t'

Execute(The deadnix command should be configurable):
  let g:ale_nix_deadnix_executable = 'foo/bar'

  AssertLinter 'foo/bar', ale#Escape('foo/bar') . ' -o json -- %t'