TST: Refactor ``test_subtracting_two_series_with_unordered_index_and_all_nan_index``

[phofl]

The test is hard to read and hard to understand. We should refactor it to make it more straightforward without those parametrizations. Pending #49442

[shogohida]

Hi @phofl, I want to work on this! However, I'm not very sure how to refactor the test because I'm new to Pandas. Could you give me some advice? It would be really helpful

[phofl]

It would be helpful to remove the parametrisation and split the content into two tests so that it is easier to read. But would be good to wait till the linked pr is merged, because it changed the behavior of the test

[shogohida]

take

[shogohida]

Thanks for your comment! Now I understand that I need to separate result and expected. I will wait until the linked PR is merged

pandas/pandas/tests/indexing/multiindex/test_multiindex.py

Lines 187 to 215 in a551f1b

	def test_subtracting_two_series_with_unordered_index_and_all_nan_index(
	self, data_result, data_expected
	):
	# GH 38439
	a_index_result = MultiIndex.from_tuples(data_result[0])
	b_index_result = MultiIndex.from_tuples(data_result[1])
	a_series_result = Series(data_result[2], index=a_index_result)
	b_series_result = Series(data_result[3], index=b_index_result)
	result = a_series_result.align(b_series_result)
	a_index_expected = MultiIndex.from_tuples(data_expected[0])
	b_index_expected = MultiIndex.from_tuples(data_expected[1])
	a_series_expected = Series(data_expected[2], index=a_index_expected)
	b_series_expected = Series(data_expected[3], index=b_index_expected)
	a_series_expected.index = a_series_expected.index.set_levels(
	[
	a_series_expected.index.levels[0].astype("float"),
	a_series_expected.index.levels[1].astype("float"),
	]
	)
	b_series_expected.index = b_series_expected.index.set_levels(
	[
	b_series_expected.index.levels[0].astype("float"),
	b_series_expected.index.levels[1].astype("float"),
	]
	)
	tm.assert_series_equal(result[0], a_series_expected)
	tm.assert_series_equal(result[1], b_series_expected)

[shogohida]

Some tests failed but I wanted to make sure if my understanding is correct at first. Can you have a look?

#49698