You're quite right!

It should be [a-zA-Z] instead of \w.

Thanks for spotting the bug, Don't Panic ;)

You might need to consider putting the border situation, i.e. when n = 5**i i = 1, 2, ..., into the testcase as well.

Since I've passed the submission test but failed my own test with the error msg: zeros(25): 5 should equal 6

It could just be like this:

Test.assert_equals(zeros(25), 6, "zeros(25)")

sorry guys, submitted accidentally while testing other's code...XD

Try to use cgi to check the content of the given str as @hlfcoding did.
e.g. print cgi.escape(str)

I agree with @Steve Ruble, the description under the 3rd assumption about "ignoring the values within the nested tags" is contradictory to the 3rd, 4th and 5th submission testcases.

Cool. Thank you for making this awesome kata!

testcase for submission might've missed the following situation:

when score of [x, x, x, y, y, y] should be Three-of-kind 'x' + Three-of-kind 'y'.

e.g. score of [1, 1, 1, 6, 6, 6] ought to be 1000 for Three-of-kind '1' plus 600 for Three-of-kind '6' = 1000 + 600 = 1600

cause i've passed it (by clicking the 'submit') when i only counted the score of one of them (Three-of-kind 'x' and Three-of-kind 'y'), while failing my own test

or i might've misunderstood the rules...XD