def METHOD_NAME(self):
    c, a = "C1", .5
    m = self.mark(color=c, alpha=a)
    assert resolve_color(m, {}) == mpl.colors.to_rgba(c, a)
    df = pd.DataFrame(index=pd.RangeIndex(10))
    cs = [c] * len(df)
    assert_array_equal(resolve_color(m, df), mpl.colors.to_rgba_array(cs, a))