The 'A' is variable, basically always equal to 1 unless you need the extra 10 then you can tack it on (10 that is). There is only a few cases where you want the 'A' to be 11.

Your function returned false for that input when it should have returned true.

for s = "xcyc"
part1 = "xc"
part2 = "cy"
: expected false to equal true

is it should returns true?

[ 'A', '7', 'K', '8', '10' ]
expected 46 to equal 36

is this right?