fix round robin

server/src/instance.rs

@@ -287,7 +287,7 @@ impl Instance {
     }
 
     fn next_round(&mut self) -> &mut Instance {
-        if self.win_condition() {
+        if self.finish_condition() {
             return self.finish();
         }
 
@@ -309,10 +309,13 @@ impl Instance {
         self
     }
 
-    fn win_condition(&self) -> bool {
+    fn finish_condition(&self) -> bool {
         match self.format {
+            // bo5 standard
             Format::Standard => self.players.iter().any(|p| p.score.wins > 2),
-            Format::RoundRobin => self.rounds.len() == self.players.len() / 2,
+
+            // everybody plays each other once
+            Format::RoundRobin => self.rounds.len() == self.players.len() - 1,
         }
     }
 
@@ -775,7 +778,7 @@ mod tests {
 
         assert_eq!(instance.phase, InstancePhase::Finished);
         assert_eq!(instance.rounds[0].len(), 8);
-        assert_eq!(instance.rounds.len(), 8);
+        assert_eq!(instance.rounds.len(), 15);
     }
 
     #[test]