Removed tests such as 1 2 3.

I also get this. Currently this kata is unsolvable in ruby. Also I'm fairly certain this is a duplicate.

Is there a way to see the sample test cases when actually doing the kata though? I couldn't find one without clicking over to the discussion and risking spoilers.

You should have sample test cases preloaded in the box which is there for your own test cases.

Sample test cases are optionally provided by the kata author.

It should say that "3" should come out to 3, "3 4" should come out to 4

This should be obvious from the sample test cases.

"2 -" should come out to -2

This isn't tested for.