code: def test_polar_no_data():
      plt.subplot(projection="polar")
      ax = plt.gca()
      assert ax.get_rmin() == 0 and ax.get_rmax() == 1
      plt.close("all")
      # Used to behave differently (by triggering an autoscale with no data).
      plt.polar()
      ax = plt.gca()
      assert ax.get_rmin() == 0 and ax.get_rmax() == 1
  
imports: import numpy
  from numpy.testing import assert_allclose
  import pytest
  import matplotlib
  from matplotlib import pyplot
  from matplotlib.testing.decorators import image_comparison, check_figures_equal
label_desc: Use image node_id 19 for calling a global function with example usage: test_polar_no_data() without return types