Colorbar.add_lines() is misused or something... #4998

======================================================================
ERROR: test suite for <class 'matplotlib.tests.test_contour.test_given_colors_levels_and_extends'>
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/suite.py", line 208, in run
    self.setUp()
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/suite.py", line 291, in setUp
    self.setupContext(ancestor)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/suite.py", line 314, in setupContext
    try_run(context, names)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/nose-1.1.2-py2.7.egg/nose/util.py", line 478, in try_run
    return func()
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/testing/decorators.py", line 154, in setup_class
    cls._func()
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/tests/test_contour.py", line 192, in test_given_colors_levels_and_extends
    plt.colorbar()
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/pyplot.py", line 2234, in colorbar
    ret = gcf().colorbar(mappable, cax = cax, ax=ax, **kw)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1570, in colorbar
    cb = cbar.colorbar_factory(cax, mappable, **kw)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/colorbar.py", line 1338, in colorbar_factory
    cb = Colorbar(cax, mappable, **kwargs)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/colorbar.py", line 905, in __init__
    self.add_lines(CS)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/colorbar.py", line 948, in add_lines
    erase=erase)
  File "/nas/home/broot/centos6/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/colorbar.py", line 542, in add_lines
    " %d vs. %d" % (len(colors), len(levels)))
ValueError: colors is not the same length as levels: 5 vs. 4

@image_comparison(baseline_images=['contour_manual_colors_and_levels'],
                  extensions=['png'], remove_text=True)
def test_given_colors_levels_and_extends():
    _, axes = plt.subplots(2, 4)

    data = np.arange(12).reshape(3, 4)

    colors = ['red', 'yellow', 'pink', 'blue', 'black']
    levels = [2, 4, 8, 10]

    for i, ax in enumerate(axes.flatten()):
        plt.sca(ax)

        filled = i % 2 == 0.
        extend = ['neither', 'min', 'max', 'both'][i // 2]

        if filled:
            last_color = -1 if extend in ['min', 'max'] else None
            plt.contourf(data, colors=colors[:last_color], levels=levels,
                         extend=extend)
        else:
            last_level = -1 if extend == 'both' else None
            plt.contour(data, colors=colors, levels=levels[:last_level],
                        extend=extend)

        plt.colorbar()