def test_combineFirst(self):
series = Series(common.makeIntIndex(20).astype(float),
index=common.makeIntIndex(20))
series_copy = series * 2
series_copy[::2] = np.NaN
# nothing used from the input
combined = series.combineFirst(series_copy)
self.assert_(np.array_equal(combined, series))
# Holes filled from input
combined = series_copy.combineFirst(series)
self.assert_(np.isfinite(combined).all())
self.assert_(np.array_equal(combined[::2], series[::2]))
self.assert_(np.array_equal(combined[1::2], series_copy[1::2]))
# mixed types
index = common.makeStringIndex(20)
floats = Series(common.randn(20), index=index)
strings = Series(common.makeStringIndex(10), index=index[::2])
combined = strings.combineFirst(floats)
common.assert_dict_equal(strings, combined, compare_keys=False)
common.assert_dict_equal(floats[1::2], combined, compare_keys=False)
# corner case
s = Series([1., 2, 3], index=[0, 1, 2])
result = s.combineFirst(Series([], index=[]))
assert_series_equal(s, result)
