`(x + 1) % 1` inside test_multi.py
#### Code Sample, a copy-pastable example if possible

https://github.com/pandas-dev/pandas/blob/93033151a8d8aaa650a81df9f41347758bf6c393/pandas/tests/indexes/test_multi.py#L170-L171

#### Problem description

I assume this is supposed to shift the labels cyclically by one. Then `% 4` and `% 2` should be used. Otherwise its at least weird to write `(x + 1) % 1` instead of `0`.
