code: def test_convert_r2_uri_to_s3_endpoint_url(r2_artifact_root):
      with mock.patch("boto3.client") as _:
          artifact_uri = posixpath.join(r2_artifact_root, "some/path")
          repo = get_artifact_repository(artifact_uri)
  
          s3_endpoint_url = repo.convert_r2_uri_to_s3_endpoint_url(
              r2_artifact_root
          )
          assert (
              s3_endpoint_url
              == "https://account.r2.cloudflarestorage.com"
          )
  
file_path: mlflow/tests/store/artifact/test_r2_artifact_repo.py
imports: import posixpath
  from unittest import mock
  from unittest.mock import ANY
  import pytest
  from mlflow.store.artifact.artifact_repository_registry import get_artifact_repository
  from mlflow.store.artifact.s3_artifact_repo import _cached_get_s3_client
  from tests.helper_functions import set_boto_credentials
label_desc: Use image node_id 5 for calling a global function with example usage: test_convert_r2_uri_to_s3_endpoint_url(r2_artifact_root) without return types