CosmicClash/server/domain/matcher_test.go

package domain

import (
	"testing"
	"time"
)

func candidate(id string, rating float64, wait time.Duration, eu, na float64, now time.Time) Candidate {
	return Candidate{TicketID: id, PlayerID: "player-" + id, Rating: rating, EnqueuedAt: now.Add(-wait), PredictedRTT: map[string]float64{"EU": eu, "NA": na}}
}

func TestSelectCandidatesNeverCrossesRTTOrMutualRatingCeilings(t *testing.T) {
	now := time.Unix(100000, 0)
	anchor := candidate("a", 1500, 0, 40, 140, now)
	players := []Candidate{
		candidate("b", 1590, 10*time.Second, 45, 40, now),
		candidate("c", 1590, 70*time.Second, 50, 50, now),
		candidate("d", 1800, 70*time.Second, 40, 40, now),
	}
	selection, err := SelectCandidates(anchor, players, 3, now)
	if err != nil {
		t.Fatal(err)
	}
	if selection.Region != "EU" || selection.WorstRTT > MaxPlacementRTT {
		t.Fatalf("bad region/RTT: %+v", selection)
	}
	if ticketIDs(selection.Players) != "a\x00b\x00c\x00" {
		t.Fatalf("selected incompatible or non-optimal set: %q", ticketIDs(selection.Players))
	}
}

func TestSelectCandidatesRequiresAnchorAndUsesDeterministicTieBreak(t *testing.T) {
	now := time.Unix(100000, 0)
	anchor := candidate("anchor", 1500, 60*time.Second, 50, 50, now)
	players := []Candidate{
		candidate("z", 1500, 10*time.Second, 50, 50, now),
		candidate("y", 1500, 10*time.Second, 50, 50, now),
		candidate("x", 1500, 10*time.Second, 50, 50, now),
	}
	selection, err := SelectCandidates(anchor, players, 3, now)
	if err != nil {
		t.Fatal(err)
	}
	if !containsTicket(selection.Players, "anchor") {
		t.Fatal("anchor was omitted")
	}
	if ticketIDs(selection.Players) != "anchor\x00x\x00y\x00" {
		t.Fatalf("tie break was not lexical: %q", ticketIDs(selection.Players))
	}
}

func TestRatingToleranceWideningIsCapped(t *testing.T) {
	if RatingTolerance(29) != 100 || RatingTolerance(30) != 125 {
		t.Fatal("30-second widening boundary is wrong")
	}
	if RatingTolerance(1000) != MaxRatingTolerance {
		t.Fatal("rating tolerance is not capped")
	}
}

func TestSelectCandidatesRejectsNoCommonRegion(t *testing.T) {
	now := time.Unix(100000, 0)
	anchor := candidate("a", 1500, 0, 101, 40, now)
	other := candidate("b", 1500, 0, 40, 101, now)
	if _, err := SelectCandidates(anchor, []Candidate{other}, 2, now); err == nil {
		t.Fatal("selected players without a common <=100ms region")
	}
}