code: def test_zeros_single():
      """Test keep single object on an empty labels matrix"""
      workspace, module = make_workspace(
          {INPUT_OBJECTS: numpy.zeros((10, 10), int)}
      )
      module.x_name.value = INPUT_OBJECTS
      module.y_name.value = OUTPUT_OBJECTS
      module.measurements[0].measurement.value = TEST_FTR
      module.filter_choice.value = (
          cellprofiler.modules.filterobjects.FI_MAXIMAL
      )
      m = workspace.measurements
      m.add_measurement(INPUT_OBJECTS, TEST_FTR, numpy.zeros((0,)))
      module.run(workspace)
      labels = workspace.object_set.get_objects(OUTPUT_OBJECTS)
      assert numpy.all(labels.segmented == 0)
  
imports: import contextlib
  import io
  import os
  import pickle
  import tempfile
  import numpy
  import pytest
  import cellprofiler_core.image
  import cellprofiler_core.measurement
  import cellprofiler_core.modules
  from cellprofiler_core.constants.measurement import FF_PARENT, FF_COUNT, FF_CHILDREN_COUNT, M_LOCATION_CENTER_X, M_LOCATION_CENTER_Y, M_LOCATION_CENTER_Z, M_NUMBER_OBJECT_NUMBER
  import cellprofiler.modules.filterobjects
  import cellprofiler_core.object
  import cellprofiler_core.pipeline
  import cellprofiler_core.preferences
  import cellprofiler_core.workspace
  import tests.frontend.modules
label_desc: Use image node_id 3 for calling a global function with example usage: test_zeros_single() without return types