Fix when no groups

src/main/java/nl/connectedit/swiss/mapper/TournamentMapper.java

@@ -94,6 +94,7 @@ public class TournamentMapper implements DtoMapper<Tournament, TournamentDto>, E
     var playersCounting = new ArrayList<Long>();
 
     for (var event : tournament.getEvents()) {
+      if (event.getGroups() != null) {
         for (var group : event.getGroups()) {
           for (var round : group.getRounds()) {
             for (var match : round.getMatches()) {
@@ -107,6 +108,7 @@ public class TournamentMapper implements DtoMapper<Tournament, TournamentDto>, E
           }
         }
       }
+    }
     return playersCounting;
   }
 
@@ -114,6 +116,7 @@ public class TournamentMapper implements DtoMapper<Tournament, TournamentDto>, E
     var playersPlaying = new ArrayList<Long>();
 
     for (var event : tournament.getEvents()) {
+      if (event.getGroups() != null) {
         for (var group : event.getGroups()) {
           for (var round : group.getRounds()) {
             for (var match : round.getMatches()) {
@@ -124,11 +127,16 @@ public class TournamentMapper implements DtoMapper<Tournament, TournamentDto>, E
           }
         }
       }
+    }
 
     return playersPlaying;
   }
 
   private List<Long> getPlayersAvailable(Tournament tournament) {
+    if (tournament.getTournamentPlayers() == null) {
+      return List.of();
+    }
+
     var playersAvailable = tournament.getTournamentPlayers()
       .stream()
       .map(TournamentPlayer::getId)