def METHOD_NAME(self):
    def check_url(url):
        import requests
        response = requests.head(url)
        # 302 corresponds to redirection and it's returned by github.
        if response.status_code not in (200, 302):
            raise RuntimeError(f'url {url} returned {response.status_code}')
    repos = get_all_registered_repos()
    assert repos
    for repo in repos:
        check_url(repo.url)
    installed_repos, root = get_installed_repos_and_root()
    assert os.path.exists(root)