How to write this TeX equation appropriately for publication?

I have a 2 variables that resemble 2 different tests. I would like to multiple it by 0.2 with conditions. If test1 is available and test2 is not (dataset would show NA), use test1. Same condition for test2, if test2 is available and test1 is not, use test2 values. If both test1 and test2 are available, then use the minimum of both value.

Below is my formula, is there a more accurate one?

$$ total score_i = 0.2*test_i\begin{cases}test1test10\\\\test2test20\\\\min(test1,test2)test1\ and\ test2 0\end{cases} $$

thank you!