also check normalize_indexer

Author: keewis

xarray/tests/test_indexing.py

@@ -275,6 +275,24 @@ def test_read_only_view(self) -> None:
 
 
 class TestLazyArray:
+    @pytest.mark.parametrize(
+        ["indexer", "size", "expected"],
+        (
+            (4, 5, 4),
+            (-1, 3, 2),
+            (slice(None), 4, slice(0, 4, 1)),
+            (slice(1, -3), 7, slice(1, 4, 1)),
+            (np.array([-1, 3, -2]), 5, np.array([4, 3, 3])),
+        ),
+    )
+    def normalize_indexer(self, indexer, size, expected):
+        actual = indexing.normalize_indexer(indexer, size)
+
+        if isinstance(expected, np.ndarray):
+            np.testing.assert_equal(actual, expected)
+        else:
+            assert actual == expected
+
     def test_slice_slice(self) -> None:
         arr = ReturnItem()
         for size in [100, 99]: