code: def testSplitRayRepoStr(self):
      url, branch = split_ray_repo_str(
          "https://github.com/ray-project/ray.git"
      )
      self.assertEqual(url, "https://github.com/ray-project/ray.git")
      self.assertEqual(branch, DEFAULT_BRANCH)
  
      url, branch = split_ray_repo_str(
          "https://github.com/ray-project/ray/tree/branch/sub"
      )
      self.assertEqual(url, "https://github.com/ray-project/ray.git")
      self.assertEqual(branch, "branch/sub")
  
      url, branch = split_ray_repo_str(
          "https://github.com/user/ray/tree/branch/sub"
      )
      self.assertEqual(url, "https://github.com/user/ray.git")
      self.assertEqual(branch, "branch/sub")
  
      url, branch = split_ray_repo_str("ray-project:branch/sub")
      self.assertEqual(url, "https://github.com/ray-project/ray.git")
      self.assertEqual(branch, "branch/sub")
  
      url, branch = split_ray_repo_str("user:branch/sub")
      self.assertEqual(url, "https://github.com/user/ray.git")
      self.assertEqual(branch, "branch/sub")
  
      url, branch = split_ray_repo_str("user")
      self.assertEqual(url, "https://github.com/user/ray.git")
      self.assertEqual(branch, DEFAULT_BRANCH)
  
imports: import os
  import sys
  import tempfile
  import unittest
  from typing import Dict, Callable
  from unittest.mock import patch
  import yaml
  from github import Repository
  from ray_release.buildkite.concurrency import get_test_resources_from_cluster_compute, get_concurrency_group
  from ray_release.buildkite.filter import filter_tests, group_tests
  from ray_release.buildkite.settings import split_ray_repo_str, get_default_settings, update_settings_from_environment, Frequency, update_settings_from_buildkite, Priority, get_test_attr_regex_filters
  from ray_release.buildkite.step import get_step, RELEASE_QUEUE_DEFAULT, RELEASE_QUEUE_CLIENT, DOCKER_PLUGIN_KEY
  from ray_release.test import Test
  from ray_release.exception import ReleaseTestConfigError
  from ray_release.wheels import DEFAULT_BRANCH
label_desc: Use image node_id 2 for calling the BuildkiteSettingsTest obj's underlying member method code with example usage: obj.testSplitRayRepoStr() without return types