What is a Test Set (Visible Verdict) in google's codejam?

The first challenge is about processing inputs and outputting results. The description of the challenge indicates the following :

Test Set 1 (Visible Verdict)
1≤T≤100.
2≤N≤100.
1≤Li≤N, for all i.
Li≠Lj, for all i≠j.

I don't understand what this means. My first impression was that these are conditions that the code has to check, so I added some validation steps in order not to process/output anything for invalid inputs for T, N or Li (ex: upon receiving a Case with duplicate integers, it breaks the last condition(?) so don't process or output anything and move on to the next case). But I still get a Test Set 1 : Wrong Answer

Thanks !