add test for 1D object array indexing (#2415)

Co-authored-by: David Tremouilles <dtremoui@ouragan>
Co-authored-by: Keewis <[email protected]>

xarray/tests/test_indexing.py

@@ -753,3 +753,16 @@ def test_create_mask_error():
 def test_posify_mask_subindexer(indices, expected):
     actual = indexing._posify_mask_subindexer(indices)
     np.testing.assert_array_equal(expected, actual)
+
+
+def test_indexing_1d_object_array():
+    items = (np.arange(3), np.arange(6))
+    arr = DataArray(np.array(items))
+
+    actual = arr[0]
+
+    expected_data = np.empty((), dtype=object)
+    expected_data[()] = items[0]
+    expected = DataArray(expected_data)
+
+    assert [actual.data.item()] == [expected.data.item()]