Add unit test

Author: dcherian

tests/test_indexing.py

@@ -424,6 +424,13 @@ def test_orthogonal_indexing_fallback_on_getitem_2d(
     np.testing.assert_array_equal(z[index], expected_result)
 
 
+def test_setitem_repeated_index():
+    array = zarr.array(data=np.zeros((4,)), chunks=(1,))
+    indexer = np.array([-1, -1, 0, 0])
+    array.oindex[(indexer,)] = [0, 1, 2, 3]
+    np.testing.assert_array_equal(array[:], np.array([3, 0, 0, 1]))
+
+
 Index = list[int] | tuple[slice | int | list[int], ...]