'Create linear locator with presets={}, numticks=2 and change it to
something else. See if change was successful. Should not exception.'

def test_set_params(self):

    loc = mticker.LinearLocator(numticks=2)
    loc.set_params(numticks=8, presets={(0, 1): []})
    assert (loc.numticks == 8)
    assert (loc.presets == {(0, 1): []})
