def test_emptyResolversList(self):
        """
        L{ResolverChain._lookup} returns a L{DomainError} failure if
        its C{resolvers} list is empty.
        """
        r = ResolverChain([])
        d = r.lookupAddress('www.example.com')
        f = self.failureResultOf(d)
        self.assertIs(f.trap(DomainError), DomainError)

        L{ResolverChain._lookup} returns a L{DomainError} failure if
        its C{resolvers} list is empty.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_resolve.py