code: def test_enhance_circles(image, module, workspace):
      i, j = numpy.mgrid[-15:16, -15:16]
  
      circle = numpy.abs(numpy.sqrt(i * i + j * j) - 6) <= 1.5
  
      image.pixel_data = circle
  
      module.method.value = "Enhance"
  
      module.enhance_method.value = "Circles"
  
      module.object_size.value = 12
  
      module.run(workspace)
  
      actual = workspace.image_set.get_image("output").pixel_data
  
      assert actual[15, 15] == 1
  
      assert numpy.all(
          actual[numpy.abs(numpy.sqrt(i * i + j * j) - 6) < 1.5] < 0.25
      )
  
imports: import io
  import os.path
  import centrosome.filter
  import numpy
  import pytest
  import scipy.ndimage
  import skimage.exposure
  import skimage.filters
  import skimage.transform
  import tests.frontend.modules
  import cellprofiler_core.image
  import cellprofiler_core.measurement
  import cellprofiler_core.module
  import cellprofiler.modules.enhanceorsuppressfeatures
  import cellprofiler_core.object
  import cellprofiler_core.pipeline
  import cellprofiler_core.preferences
  import cellprofiler_core.workspace
  import tests.frontend
label_desc: Use image node_id 21 for calling a global function with example usage: test_enhance_circles(image, module, workspace) without return types