TST: Add regression test for NaN sparse columns (#52772)

* Add test for GH 27781 * Modify test for GH 27781
pandas-dev · Apr 19, 2023 · e96054a · e96054a
1 parent fc4ff26
commit e96054a
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/pandas/tests/arrays/sparse/test_array.py b/pandas/tests/arrays/sparse/test_array.py
@@ -478,3 +478,15 @@ def test_drop_duplicates_fill_value():
     result = df.drop_duplicates()
     expected = pd.DataFrame({i: SparseArray([0.0], fill_value=0) for i in range(5)})
     tm.assert_frame_equal(result, expected)
+
+
+def test_zero_sparse_column():
+    # GH 27781
+    df1 = pd.DataFrame({"A": SparseArray([0, 0, 0]), "B": [1, 2, 3]})
+    df2 = pd.DataFrame({"A": SparseArray([0, 1, 0]), "B": [1, 2, 3]})
+    result = df1.loc[df1["B"] != 2]
+    expected = df2.loc[df2["B"] != 2]
+    tm.assert_frame_equal(result, expected)
+
+    expected = pd.DataFrame({"A": SparseArray([0, 0]), "B": [1, 3]}, index=[0, 2])
+    tm.assert_frame_equal(result, expected)