code: def test_roc_auc(self, n_samples):
      self.run_roc_auc_binary("hist", n_samples)
  
imports: import numpy
  import pytest
  import xgboost
  from xgboost import testing
  from xgboost.testing.metrics import check_precision_score, check_quantile_error
label_desc: Use image node_id 9 for calling the TestEvalMetrics obj's underlying member method code with example usage: obj.test_roc_auc(n_samples) without return types