'5' is not an alphabetical character, it is an alphanumeric character. The instructions explicitly state that only alphabetical characters should be considered part of "words" so the output expected should be "d3y sat".

Ah! I see why it is still part of it now. The instructions seemed contradictory but I get how it all works now... now that I have code that perfectly eliminates all of them. XD

This kata was great! I hit the reset button after 4.5 hours of the pain of making the wrong code work flawlessly (LOL!) and got it within 45 minutes. I need to learn how to remember what I'm doing better! XD

I had similar problem. Make sure you are not using global variables. When performing tests, they are not refreshed.
I had identical code that worked on my machine, but didn't work in here

The brackets you see is the way how JUnit formats the value in attempt to show the difference between actual and expected values. Tests do not expect these brackets to occur in the returned value, it's just how the value is formatted by JUnit assertion method.

Test seems incorrect according to task (Java):
Input: 'doggy5sat' expected:<d[3y5sa]t>
I assume d3y5sat is expected, without brackets