text: # -*- coding: utf-8 -*-
  # Licensed under a 3-clause BSD style license - see LICENSE.rst
  
  from __future__ import (absolute_import, division, print_function,
                          unicode_literals)
  
  import io
  
  import pytest
  
  try:
      import matplotlib.pyplot as plt
  except ImportError:
      HAS_PLT = False
  else:
      HAS_PLT = True
  
  from ... import units as u
  from ...coordinates import Angle
  from ..units import quantity_support
  
  
  @pytest.mark.skipif('not HAS_PLT')
  def test_units():
      plt.figure()
  
      with quantity_support():
          buff = io.BytesIO()
  
          plt.plot([1, 2, 3] * u.m, [3, 4, 5] * u.kg, label='label')
          plt.plot([105, 210, 315] * u.cm, [3050, 3025, 3010] * u.g)
          plt.legend()
          # Also test fill_between, which requires actual conversion to ndarray
          # with numpy >=1.10 (#4654).
          plt.fill_between([1, 3] * u.m, [3, 5] * u.kg, [3050, 3010] * u.g)
          plt.savefig(buff, format='svg')
  
          assert plt.gca().xaxis.get_units() == u.m
          assert plt.gca().yaxis.get_units() == u.kg
  
      plt.clf()
  
  
  @pytest.mark.skipif('not HAS_PLT')
  def test_units_errbarr():
      pytest.importorskip("matplotlib", minversion="2.2")
      plt.figure()
  
      with quantity_support():
          x = [1, 2, 3] * u.s
          y = [1, 2, 3] * u.m
          yerr = [3, 2, 1] * u.cm
  
          fig, ax = plt.subplots()
          ax.errorbar(x, y, yerr=yerr)
  
          assert ax.xaxis.get_units() == u.s
          assert ax.yaxis.get_units() == u.m
  
      plt.clf()
  
  
  @pytest.mark.skipif('not HAS_PLT')
  def test_incompatible_units():
      # NOTE: minversion check does not work properly for matplotlib dev.
      try:
          # https://github.com/matplotlib/matplotlib/pull/13005
          from matplotlib.units import ConversionError
      except ImportError:
          err_type = u.UnitConversionError
      else:
          err_type = ConversionError
  
      plt.figure()
  
      with quantity_support():
          plt.plot([1, 2, 3] * u.m)
          with pytest.raises(err_type):
              plt.plot([105, 210, 315] * u.kg)
  
      plt.clf()
  
  
  @pytest.mark.skipif('not HAS_PLT')
  def test_quantity_subclass():
      """Check that subclasses are recognized.
  
      This sadly is not done by matplotlib.units itself, though
      there is a PR to change it:
      https://github.com/matplotlib/matplotlib/pull/13536
      """
      plt.figure()
  
      with quantity_support():
          plt.scatter(Angle([1, 2, 3], u.deg), [3, 4, 5] * u.kg)
          plt.scatter([105, 210, 315] * u.arcsec, [3050, 3025, 3010] * u.g)
          plt.plot(Angle([105, 210, 315], u.arcsec), [3050, 3025, 3010] * u.g)
  
          assert plt.gca().xaxis.get_units() == u.deg
          assert plt.gca().yaxis.get_units() == u.kg
  
  
  @pytest.mark.skipif('not HAS_PLT')
  def test_nested():
  
      with quantity_support():
  
          with quantity_support():
  
              fig = plt.figure()
              ax = fig.add_subplot(1, 1, 1)
              ax.scatter(Angle([1, 2, 3], u.deg), [3, 4, 5] * u.kg)
  
              assert ax.xaxis.get_units() == u.deg
              assert ax.yaxis.get_units() == u.kg
  
          fig = plt.figure()
          ax = fig.add_subplot(1, 1, 1)
          ax.scatter(Angle([1, 2, 3], u.arcsec), [3, 4, 5] * u.pc)
  
          assert ax.xaxis.get_units() == u.arcsec
          assert ax.yaxis.get_units() == u.pc
  