Before:
  call ale#assert#SetUpLinterTest('perl6', 'perl6')

After:
  call ale#assert#TearDownLinterTest()

Execute(The default Perl6 command callback should be correct):
  AssertLinter 'perl6', 'perl6' . ' -c -Ilib %t'

Execute(Overriding the executable and command should work):
  let b:ale_perl6_perl6_executable = 'foobar'
  let b:ale_perl6_perl6_options = '-w'

  AssertLinter 'foobar', 'foobar' . ' -w %t'