Greatly enjoyed solving this. Thanks for making it!

But I do want to bemoan the choice to have the zero tile in the bottom right rather than the top left, haha.

Done. Thanks!

Fixed.

Oops, forgot to port that over.

I think that fixed it. Try again!

Ok, the randomized tests are now scrambled versions of a solved board.

Interesting. I'm going to change how the random boards are created and then get back to this.

Also, any feedback on better wording for the instructions is welcome.

I'm assuming that was the case.

Certainly not. Unless I did something incorrectly, its still possible for the random board function to return a solved board, it's just significantly unlikely.

I will refactor it to just scrambling a correct board.

Good to know about logging. I didn't know it would output if failed. I had run into a few kata that didn't seem to do that, which was frustrating. I removed the logs.

No. Just let expects = solvedCheck(testBoard);

Oops. Fixed.

Did you mix this up with the minimum value for N ?

You're exactly right. Fixed!

(and the second sample tests has two threes and no two)

In my mind, this is still an unsolved puzzle, but I can certainly change it.

Ok, done!

...
let testBoard = Math.floor(Math.random() * 4) ? mkRandBoard(size) : mkSolvedBoard(size);
...

Thanks for your help. If you have time and can offer some clarity on the remaining issue left by FArekkusu, I would appreciate it. :)

Oh. What if I make it 50/50 that each random test will expect true? Is that what you're looking for?

Ah ok. I'm not sure how to implement a random test that garauntees at least some results that expect true. If I have to make them completely random, then the chance of that is just going to be very small.

I apologize if I'm misunderstanding.

If the issue is that there are no random tests that will expect true, then I think no adjustments are necessary. The first section of tests are random sizes that expect true.