code: def test_image_equal_clims(texture_format, num_channels):
      """Test image visual with equal clims."""
      size = (40, 40)
      input_dtype = np.uint8
      shape = size + (num_channels,) if num_channels > 0 else size
      np.random.seed(0)
      data = _make_test_data(shape, input_dtype)
      with TestingCanvas(size=size[::-1], bgcolor="w") as c:
          Image(
              data,
              cmap="viridis",
              texture_format=texture_format,
              clim=(128.0, 128.0),
              parent=c.scene,
          )
          rendered = c.render()[..., :3]
  
          if num_channels >= 3:
              # RGBs don't have colormaps
              assert rendered.sum() == 0
              return
  
          # not all black
          assert rendered.sum() != 0
          # not all white
          assert rendered.sum() != 255 * rendered.size
          # should be all the same value
          r_unique = np.unique(rendered[..., 0])
          g_unique = np.unique(rendered[..., 1])
          b_unique = np.unique(rendered[..., 2])
          assert r_unique.size == 1
          assert g_unique.size == 1
          assert b_unique.size == 1
  
file_path: vispy/vispy/visuals/tests/test_image.py
imports: from unittest import mock
  from vispy.scene import Image, PanZoomCamera
  from vispy.testing import requires_application, TestingCanvas, run_tests_if_main, IS_CI
  from vispy.testing.image_tester import assert_image_approved, downsample
  import numpy
  import pytest
  from vispy.testing.rendered_array_tester import compare_render, max_for_dtype
label_desc: Use image node_id 9 for calling a global function with example usage: test_image_equal_clims(texture_format, num_channels) without return types