multiindex lexsort depth test

Author: jackgoldsmith4

pandas/tests/indexes/multi/test_setops.py

@@ -544,3 +544,20 @@ def test_union_duplicates(index, request):
 
     result = mi2.union(mi1)
     tm.assert_index_equal(result, mi2.sort_values())
+
+@pytest.mark.parametrize(
+    "levels1, levels2, codes1, codes2, names",
+    [
+        ([['2018', 'a', 'c', 'e', 'num', 'oan', 'vol'], [1970, '']],
+        [['e', 'num', 'oan', 'vol', 'year'], ['']], [[3, 6, 4, ], [1, 1, 1]],
+        [[3, 1, 4, 1, 0], [0, 0, 0, 0, 0]], ['variable', 'cit_year']),
+    ],
+)
+def test_intersection_lexsort_depth(levels1, levels2, codes1, codes2, names):
+    # GH#25169
+    mi1 = MultiIndex(levels=levels1, codes=codes2, names=names)
+    mi2 = MultiIndex(levels=levels2, codes=codes2, names=names)
+    mi_int = mi1.intersection(mi2)
+    expected = 0
+
+    assert mi_int.lexsort_depth.equals(expected)