TST: Add test to verify 'dropna' behaviour on SparseArray

[MBrouns]

verify that calling dropna on a pd.SparseArray does not inadvertently drop non-na records on both DataFrames and the SparseArray itself.

• closes DataFrame.dropna() not working with sparse columns #28287
• tests added / passed
• passes black pandas
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry (not applicable?)

[charlesdong1991]

thanks! couple nitpicks, and CI failure is irrelevant.

[MBrouns]

Thanks, incorporated the feedback!

[jorisvandenbossche]

Thanks for the contribution!

The test you added looks good, but I think it would be nice to directly include a test for "invert" as well. See the comment from the original issues: #28287 (comment)

[MBrouns]

The test you added looks good, but I think it would be nice to directly include a test for "invert" as well. See the comment from the original issues: #28287 (comment)

Isn't that already covered by

pandas/pandas/tests/arrays/sparse/test_arithmetics.py

Lines 466 to 480 in 72aed3e

	@pytest.mark.parametrize("fill_value", [True, False])
	def test_invert(fill_value):
	arr = np.array([True, False, False, True])
	sparray = SparseArray(arr, fill_value=fill_value)
	result = ~sparray
	expected = SparseArray(~arr, fill_value=not fill_value)
	tm.assert_sp_array_equal(result, expected)
	result = ~pd.Series(sparray)
	expected = pd.Series(expected)
	tm.assert_series_equal(result, expected)
	result = ~pd.DataFrame({"A": sparray})
	expected = pd.DataFrame({"A": expected})
	tm.assert_frame_equal(result, expected)

?

[jorisvandenbossche]

Isn't that already covered by

That indeed looks to be the case, thanks for checking!

[jorisvandenbossche]

Thanks for the update!

[jorisvandenbossche]

(failures are all the html failures)

[jorisvandenbossche]

Thanks!