code: def test_run_context_provider_registry_with_installed_plugin():
      """This test requires the package in tests/resources/mlflow-test-plugin to be installed"""
  
      reload(mlflow.tracking.request_header.registry)
  
      from mlflow_test_plugin.request_header_provider import (
          PluginRequestHeaderProvider,
      )
  
      assert (
          PluginRequestHeaderProvider
          in _currently_registered_request_header_provider_classes()
      )
  
      # The test plugin's request header provider always returns False from in_context to avoid
      # polluting request headers in developers' environments. The following mock overrides this to
      # perform the integration test.
      with mock.patch.object(
          PluginRequestHeaderProvider, "in_context", return_value=True
      ):
          assert resolve_request_headers()["test"] == "header"
  
file_path: mlflow/tests/tracking/request_header/test_registry.py
imports: from importlib import reload
  from unittest import mock
  import pytest
  import mlflow.tracking.request_header.registry
  from mlflow.tracking.request_header.databricks_request_header_provider import DatabricksRequestHeaderProvider
  from mlflow.tracking.request_header.registry import RequestHeaderProviderRegistry, resolve_request_headers
label_desc: Use image node_id 8 for calling a global function with example usage: test_run_context_provider_registry_with_installed_plugin() without return types