What is this magic spell?

Note to self: Math is not your strong suite, consider being better.

Thank you for the validation!

I managed to wrangle my way around it by discovering the %g character class in lua but for a good hour there I was pulling out my hair...

You are right and the random inputs you see are a result of a sloppy authoring, which was unfortunately very common long time ago. The description should define what a "word" is, or tests should use some intuitive, non-surprising interpretation. One hint can be the rank of the kata, where a 7 kyu task would usually not require you to handle any complex cases, but it's a bit of handwaving the problem away.

Call me pedantic but a random list of characters is not what i would call A WORD.

But what really gripes me is that your rules for deciding what a "word" is are never defined.

For example, in one of your tests "Let's" is defined as a whole word and even though the 's' sits after an apostrophe, the test does not qualify this as a single letter word. That seems fair to me.

But in your random tests I was given apprently this phrase.

"eQnsghc' xN378hr43hHv1kz O5xF2TuTF 9xN8uJWxQeeH hy'c'jaX6fU ixFBC' 8MT2g '6cdNKKKJwK2Ws9 LVu k4UkP 6sgnrftSHF ba6Xu83mHF6m PWD GcXMUC8Kr1n8GZ qfGknKV4Zcq 1MwvcXRz1e7 V87dPg FKdz7y BW61E7N9 "

Now my code provided 3 but the expected result was 1...
So I'm left with only 2 assumptions...

Either the phrase "hy'c'jaX6fU ixFBC'" wants me to see the 'c' as a single letter word
OR
the phrase "8MT2g" is actually two words "MT" and "g"...

Both conclusions actually contradicts another test: "1Ay4Ke5MsW'Ib" which wants a result of 13!
Meaning that both numbers and apostrophes count towards a word size!

This is doing my head in.. Can someone smarter than me please tell me why I'm losing the plot here?