code: def test_plot_glass_brain_negative_vmin_with_plot_abs(img_3d_mni):
      """Test that warning is thrown if plot_abs is True and vmin is negative."""
      warning_message = "vmin is negative but plot_abs is True"
      with pytest.warns(UserWarning, match=warning_message):
          plot_glass_brain(img_3d_mni, vmin=-2, plot_abs=True)
  
file_path: nilearn/nilearn/plotting/tests/test_img_plotting/test_plot_glass_brain.py
imports: import matplotlib.pyplot
  import numpy
  import pytest
  from nibabel import Nifti1Image
  from nilearn.image import get_data
  from nilearn.plotting import plot_glass_brain
label_desc: Use image node_id 9 for calling a global function with example usage: test_plot_glass_brain_negative_vmin_with_plot_abs(img_3d_mni) without return types