code: def test_signed_image():
      plt.figure()
      im_signed = np.array([[-0.5, -0.2], [0.1, 0.4]])
  
      with expected_warnings(
          imshow_expected_warnings + [r"CObject type is marked|\A\Z"]
      ):
          ax_im = io.imshow(im_signed)
      assert ax_im.get_clim() == (-0.5, 0.5)
      assert n_subplots(ax_im) == 2
      assert ax_im.colorbar is not None
  
file_path: scikit-image/skimage/io/tests/test_mpl_imshow.py
imports: import numpy
  import pytest
  from skimage import io
  from skimage._shared._warnings import expected_warnings
label_desc: Use image node_id 9 for calling a global function with example usage: test_signed_image() without return types