code: def _make_test_data(shape, input_dtype):
      one_third = shape[0] // 3
      two_third = 2 * one_third
      data = np.zeros(shape, dtype=np.float64)
      # 0.00 | 1.00 | 0.00
      # 0.50 | 0.00 | 0.25
      # 0.00 | 0.00 | 0.00
      data[:, :one_third, one_third:two_third] = 1.0
      data[:, one_third:two_third, :one_third] = 0.5
      data[:, one_third:two_third, two_third:] = 0.25
      max_val = max_for_dtype(input_dtype)
      if max_val != 1:
          data *= max_val
      data = data.astype(input_dtype)
      return data
  
imports: import pytest
  import numpy
  from vispy import scene
  from vispy.testing import TestingCanvas, requires_application, run_tests_if_main, requires_pyopengl, raises
  from vispy.testing.image_tester import assert_image_approved, downsample
  from vispy.testing.rendered_array_tester import compare_render, max_for_dtype
label_desc: Use image node_id 7 for calling a global function with example usage: _make_test_data(shape, input_dtype) and returns: data