It looks very good! Lots of thanks.

Added, ping me on gitter if you think I've done something wrong or missed something.

You returned (7)(11**2)(17)(2**2)(3**3)(5) where the prime numbers are not in increasing order.
Before posting issues please look at the top of the page to see how many people passed the kata (176 in golang); if this number is high chances are that your code is wrong somewhere.

Tests in Golang looks not correct. They are trying to assert on random order.
condition in Kata Details
with the p(i) in increasing order and n(i) empty if n(i) is 1
Tests failing on above condition.
Example, when I attempted, I get
Expected <string>: (7)(11**2)(17)(2**2)(3**3)(5) to equal <string>: (2**2)(3**3)(5)(7)(11**2)(17)
So, based on above condition, my solution is correct, but from Test output, Expected string is in random order.