code: def test_roc(dummy_classifier):
      *_, y_test, _, y_probas = dummy_classifier
      r = roc(y_test, y_probas)
  
      assert r.value.data[0] == [0, 0.0, 0.0]
  
file_path: wandb/tests/pytest_tests/unit_tests/test_plots.py
imports: import pytest
  from sklearn.naive_bayes import MultinomialNB
  from wandb.plots.heatmap import heatmap
  from wandb.plots.precision_recall import precision_recall
  from wandb.plots.roc import roc
label_desc: Use image node_id 2 for calling a global function with example usage: test_roc(dummy_classifier) without return types