code: def test_no_objects():
      """Test images with no objects"""
      labels = numpy.zeros((10, 10), int)
      i, j = numpy.mgrid[0:10, 0:10]
      image1 = ((i + j) % 2).astype(float)
      image2 = image1.copy()
      i1 = cellprofiler_core.image.Image(image1)
      i2 = cellprofiler_core.image.Image(image2)
      o = cellprofiler_core.object.Objects()
      o.segmented = labels
      workspace, module = make_workspace(i1, i2, o)
      module.run(workspace)
      m = workspace.measurements
      mi = module.get_measurement_images(
          None, OBJECTS_NAME, "Correlation", "Correlation"
      )
      corr = m.get_current_measurement(
          OBJECTS_NAME, "Correlation_Correlation_%s" % mi[0]
      )
      assert len(corr) == 0
      assert len(m.get_object_names()) == 2
      assert OBJECTS_NAME in m.get_object_names()
      columns = module.get_measurement_columns(None)
      image_features = m.get_feature_names("Image")
      object_features = m.get_feature_names(OBJECTS_NAME)
      assert len(columns) == len(image_features) + len(object_features)
      for column in columns:
          if column[0] == "Image":
              assert column[1] in image_features
          else:
              assert column[0] == OBJECTS_NAME
              assert column[1] in object_features
  
imports: import numpy
  import six.moves
  import cellprofiler_core.image
  import cellprofiler_core.measurement
  from cellprofiler_core.constants.measurement import COLTYPE_FLOAT
  import cellprofiler.modules.measurecolocalization
  import cellprofiler_core.object
  import cellprofiler_core.pipeline
  import cellprofiler_core.workspace
  import tests.frontend.modules
label_desc: Use image node_id 17 for calling a global function with example usage: test_no_objects() without return types