===================================================================== ERRORS =====================================================================
___________________________________________________ ERROR at setup of test_bar3d[0-bar3d-png] ____________________________________________________

self = <matplotlib.testing.decorators.ImageComparisonDecorator object at 0x7f87fe538ba8>

    def setup(self):
        func = self.func
        plt.close('all')
        self.setup_class()
        try:
            matplotlib.style.use(self.style)
            matplotlib.testing.set_font_settings_for_testing()
>           func()

../matplotlib/testing/decorators.py:259:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
tests/test_mplot3d.py:15: in test_bar3d
    ax = fig.add_subplot(111, projection='3d')
../matplotlib/figure.py:1015: in add_subplot
    a = subplot_class_factory(projection_class)(self, *args, **kwargs)
../matplotlib/axes/_subplots.py:73: in __init__
    self._axes_class.__init__(self, fig, self.figbox, **kwargs)
mplot3d/axes3d.py:98: in __init__
    *args, **kwargs)
../matplotlib/axes/_base.py:540: in __init__
    self.cla()
mplot3d/axes3d.py:1077: in cla
    self.set_zlim(0, 1)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <matplotlib.axes._subplots.Axes3DSubplot object at 0x7f87fb427828>, bottom = 0, top = 1, emit = True, auto = False, kw = {}
old_bottom = 0.0, old_top = 1.0

    def set_zlim3d(self, bottom=None, top=None, emit=True, auto=False, **kw):
        """
            Set 3D z limits.

            See :meth:`matplotlib.axes.Axes.set_ylim` for full documentation

            """
        if 'zmin' in kw:
            bottom = kw.pop('zmin')
        if 'zmax' in kw:
            top = kw.pop('zmax')
        if kw:
            raise ValueError("unrecognized kwargs: %s" % list(kw))

        if top is None and cbook.iterable(bottom):
            bottom, top = bottom

        self._process_unit_info(zdata=(bottom, top))
        if bottom is not None:
            bottom = self.convert_zunits(bottom)
        if top is not None:
            top = self.convert_zunits(top)

        old_bottom, old_top = self.get_zlim()
        if bottom is None:
            bottom = old_bottom
        if top is None:
            top = old_top

        if top == bottom:
            warnings.warn(('Attempting to set identical bottom==top results\n'
                     'in singular transformations; automatically expanding.\n'

                     'bottom=%s, top=%s') % (bottom, top))
        bottom, top = mtransforms.nonsingular(bottom, top, increasing=False)
        bottom, top = self.zaxis.limit_range_for_scale(bottom, top)
        self.zz_viewLim.intervalx = (bottom, top)

        if auto is not None:
            self._autoscaleZon = bool(auto)

        if emit:
>           self.callbacks.process('zlim_changed', self)
E           AttributeError: 'Axes3DSubplot' object has no attribute 'callbacks'

mplot3d/axes3d.py:737: AttributeError