There's a bit of LaTeX math code in a comment in a test file:
```
.. math:: L = 10 \cdot \\log_{10}{\\left(\\frac{MS}{p_r^2} \\right)}
```
which of course should be `\\cdot`.
I could patch it, but I think skipping deprecation warnings in tests is
probably ok... (If nothing else it's easier.)
(cherry picked from commit dbc085cb44b90e4d533b6a24b7c9ca3c2c93d5e1)