[
  {
    "method": "ListDocuments",
    "client": "DocumentServiceClient",
    "arguments": {
      "parent": "projects/${PROJECT_ID}/locations/global/dataStores/default_data_store/branches/default_branch"
    }
  }
]
Add smoke test for Google.Cloud.DiscoveryEngine.V1Beta
tests: Add smoke test for Google.Cloud.DiscoveryEngine.V1Beta
