code: def test_no_deprecation_on_empty_data():
      """
      Smoke test to check that no deprecation warning is emitted. See #22640.
      """
      f, ax = plt.subplots()
      ax.xaxis.update_units(["a", "b"])
      ax.plot([], [])
  
imports: import warnings
  import pytest
  import numpy
  import matplotlib
  from matplotlib.axes import Axes
  import matplotlib.pyplot
  import matplotlib.category
  from matplotlib.testing.decorators import check_figures_equal
label_desc: Use image node_id 3 for calling a global function with example usage: test_no_deprecation_on_empty_data() without return types