Merge #4480

4480: Fix "insert peer invariant test" r=bolt12 a=bolt12

This test checks that newly added peer is never in the 20% worst performing peers (if there are at least 5 results). However we were not checking that the list had at least 5 results.

Fixes #4092 

Co-authored-by: Armando Santos <armando@well-typed.com>

ouroboros-network/test/Test/Ouroboros/Network/PeerSelection/PeerMetric.hs

@@ -278,7 +278,7 @@ prop_insert_peer script =
     checkResult name peer joinedAt m =
           (\peers -> counterexample (name ++ ": peer (" ++ show peer ++ ") member of "
                                           ++ show (peers, m'))
-                                    (Set.notMember peer peers))
+                                    (Set.size peers < 5 || Set.notMember peer peers))
         . Set.fromList
         . map fst
         . take (size `div` 5)
@@ -293,7 +293,6 @@ prop_insert_peer script =
                        joinedAt
         size = Map.size m
 
-
 -- | Check that the results are always positive.
 --
 prop_metrics_are_bounded :: FixedScript -> Property