code: def test_all_equal(self):
      # If all q-vals are equal, then all splats must be on the surface level.
      N, H, W, K = 2, 3, 4, 5
      q_depth = torch.ones((N, H, W, K)) * 0.1234
      occlusion_layers = _compute_occlusion_layers(q_depth)
      self.assertClose(
          occlusion_layers, torch.zeros(N, H, W, 9).long(), atol=0.0
      )
  
imports: import unittest
  import torch
  from pytorch3d.common.compat import meshgrid_ij
  from pytorch3d.renderer.cameras import FoVPerspectiveCameras
  from pytorch3d.renderer.splatter_blend import _compute_occlusion_layers, _compute_splatted_colors_and_weights, _compute_splatting_colors_and_weights, _get_splat_kernel_normalization, _normalize_and_compose_all_layers, _offset_splats, _precompute, _prepare_pixels_and_colors
  from .common_testing import TestCaseMixin
label_desc: Use image node_id 2 for calling the TestComputeOcclusionLayers obj's underlying member method code with example usage: obj.test_all_equal() without return types