TST Add test for loc on sparse dataframes

pandas/tests/indexing/test_loc.py

@@ -1163,6 +1163,25 @@ def test_loc_getitem_listlike_all_retains_sparse(self):
  result = df.loc[[0, 1]]
  tm.assert_frame_equal(result, df)
 
+ @td.skip_if_no_scipy
+ def test_loc_sparse_frame(self):
+ # GH34687
+ from scipy.sparse import eye
+
+ df = DataFrame.sparse.from_spmatrix(eye(5))
+ result = df.loc[range(2)]
+ expected = DataFrame(
+ [[1.0, 0.0, 0.0, 0.0, 0.0], [0.0, 1.0, 0.0, 0.0, 0.0]],
+ dtype=SparseDtype("float64", 0.0),
+ )
+ tm.assert_frame_equal(result, expected)
+
+ result = df.loc[range(2)].loc[range(1)]
+ expected = DataFrame(
+ [[1.0, 0.0, 0.0, 0.0, 0.0]], dtype=SparseDtype("float64", 0.0)
+ )
+ tm.assert_frame_equal(result, expected)
+
  @pytest.mark.parametrize("key_type", [iter, np.array, Series, Index])
  def test_loc_getitem_iterable(self, float_frame, key_type):
  idx = key_type(["A", "B", "C"])