fix(arena): improve containment and boss idle

design/log.md

@@ -6,6 +6,13 @@ description: Chronological record of material decisions affecting the Spigot Tyr
 
 # Spigot Tyrant Design Log
 
+## 2026-08-23 — Arena containment and idle boss corrected
+
+- Corrected shared-arena containment with a validated 12-block barrier wall extending below the arena floor and active-fight block placement and breaking protection.
+- Kept red or blue role particles visible at multiple wall heights during fights so challengers can see the otherwise invisible barrier from inside.
+- Arena bosses now remain AI-disabled at the center until an eligible challenger enters, move normally within the arena during combat, and return healed and idle only on reset or boundary escape.
+- Verified wall geometry, safe restoration, boundary visibility policy, build protection, idle/combat boss transitions, configuration validation, compiler warnings, 119 automated tests, and packaging with `./gradlew clean check jar`.
+
 ## 2026-08-23 — Shared Tyrant and Vigilante arena succession completed
 
 - Completed US-020 and reopened related succession, inactivity, administration, configuration, and Vigilante-arena stories so non-player Tyrant replacement is earned rather than random.

design/user-stories/us-012-configure-and-persist-state.md

@@ -11,7 +11,7 @@ As a **server operator**, I want configurable and durable game behavior so that
 
 ## Acceptance criteria
 
-- [x] Configuration covers ranges, durations, cooldowns, inactivity and maintenance intervals, effect levels and caps, mob restrictions, item materials and names, messages, timer behavior, and shared-role-arena boss balance.
+- [x] Configuration covers ranges, durations, cooldowns, inactivity and maintenance intervals, effect levels and caps, mob restrictions, item materials and names, messages, timer behavior, shared-role-arena boss balance, and a validated barrier wall height defaulting to 12 blocks.
 - [x] Defaults match the approved user stories, including a 50-block Tyrant range and Follower range, seven-day opt-out, 48-hour inactivity, and one-minute role maintenance.
 - [x] Invalid required configuration prevents partial plugin initialization and produces a clear server log message.
 - [x] UUID-keyed state stores lifecycle, current and pending roles, assignments, login history, participation, reign progression, purchases, choices, cooldowns, paused time, item delivery, and captured mobs; the administrator-set arena center is durable across restarts.

design/user-stories/us-019-claim-vigilante-in-arena.md

@@ -17,11 +17,14 @@ As an **opted-in participant**, I want a visible one-player boss challenge for a
 - [x] The challenge boss defaults to an armored, 80-health enhanced zombie, does not burn in sunlight, and remains within a default 10-block-radius arena.
 - [x] All online opted-in players are told when the role opens and receive the arena world and coordinates; opted-in players receive the same notice when they log in while it remains open, and opted-out players do not.
 - [x] Exactly one eligible opted-in non-Tyrant player may enter as challenger, including when entry is attempted by walking or teleportation.
-- [x] Starting a fight replaces the passive particle boundary with temporary actual `BARRIER` blocks that are removed safely without permanently changing existing blocks.
+- [x] Starting a fight builds temporary actual `BARRIER` blocks from one block below the arena floor through a default 12-block wall height, without permanently changing existing blocks.
+- [x] Role-colored boundary particles remain visible from inside and outside an active fight at multiple wall heights.
 - [x] Any non-challenger who enters or respawns inside the arena is moved safely outside it.
 - [x] Existing mobs in the arena and mobs that spawn or enter it are removed while preserving the arena boss.
+- [x] With no challenger, the boss remains AI-disabled at the arena center; entry enables its AI and target, while reset restores full health, center position, no target, and disabled AI.
 - [x] The boss attacks only the active challenger, and only that challenger can damage the boss.
 - [x] Challenger death, disconnect, or leaving by any mechanism ends the fight and resets the boss to full health at its spawn; death counts as leaving and the same player may retry immediately.
+- [x] Block placement and breaking are denied inside the arena during an active fight so players cannot build over or modify the boundary.
 - [x] Killing the boss assigns the challenger as Vigilante, removes the boss and barriers, and restores the passive particle boundary.
 - [x] Pausing, resetting, restarting, reloading, and repeated or concurrent events cannot duplicate the boss, barriers, challenger, or Vigilante assignment.
 - [x] If the arena is not configured when a challenge should open, the Vigilante remains vacant and administrators receive a clear warning.

design/user-stories/us-020-claim-tyrant-in-arena.md

@@ -15,7 +15,7 @@ As an **opted-in participant**, I want to earn a vacant Tyrant role through the
 - [x] Tyrant death without a player killer, Tyrant inactivity, and Tyrant relinquishment end the reign, clear all role-side assignments, and open the shared arena with no active or pending Tyrant.
 - [x] The shared arena opens only one role challenge at a time: a vacant Tyrant takes priority, and the Vigilante challenge can open only after a Tyrant becomes active.
 - [x] The passive arena boundary uses red particles for an open Tyrant challenge, blue particles for an open Vigilante challenge, and a neutral marker while neither role challenge is open.
-- [x] The Tyrant challenge uses the existing configured arena, boss balance, mob exclusion, one-challenger barrier, containment, reset, notification, and missing-location rules.
+- [x] The Tyrant challenge uses the existing configured arena, boss balance, tall visible one-challenger barrier, block-change protection, idle-center boss behavior, containment, reset, notification, and missing-location rules.
 - [x] An eligible opted-in participant, including the former Tyrant, may challenge for the vacant Tyrant role; an active Tyrant cannot enter any arena fight.
 - [x] Defeating the Tyrant challenge boss assigns the challenger as Tyrant with level zero, no purchases, and exactly one starting unlock choice.
 - [x] Completing the Tyrant challenge immediately permits the blue Vigilante challenge to open at the same location when the Vigilante role is vacant.

src/main/java/games/dmg/spigottyrant/ArenaBossState.java

@@ -0,0 +1,22 @@
+package games.dmg.spigottyrant;
+
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+import org.bukkit.entity.Zombie;
+
+final class ArenaBossState {
+    private ArenaBossState() {
+    }
+
+    static void idle(Zombie boss, Location center, double health) {
+        boss.setAI(false);
+        boss.setTarget(null);
+        boss.setHealth(health);
+        boss.teleport(center);
+    }
+
+    static void engage(Zombie boss, Player challenger) {
+        boss.setAI(true);
+        boss.setTarget(challenger);
+    }
+}

src/main/java/games/dmg/spigottyrant/ArenaBuildProtection.java

@@ -0,0 +1,20 @@
+package games.dmg.spigottyrant;
+
+final class ArenaBuildProtection {
+    private ArenaBuildProtection() {
+    }
+
+    static boolean isProtected(
+        boolean fightActive,
+        ArenaLocation center,
+        double radius,
+        String worldName,
+        double x,
+        double y,
+        double z
+    ) {
+        return fightActive && ArenaGeometry.contains(
+            center, radius, worldName, x, y, z
+        );
+    }
+}

src/main/java/games/dmg/spigottyrant/PluginSettings.java

@@ -13,6 +13,7 @@ public record PluginSettings(
     double tyrantRangeBlocks,
     double followerRangeBlocks,
     double vigilanteArenaRadiusBlocks,
+    int arenaBarrierHeightBlocks,
     double vigilanteBossHealth,
     double vigilanteBossDamage,
     double vigilanteBossArmor,
@@ -53,6 +54,11 @@ public record PluginSettings(
         requireFiniteRange(
             vigilanteArenaRadiusBlocks, 1.0, 512.0, "vigilante-arena-radius-blocks"
         );
+        if (arenaBarrierHeightBlocks < 3 || arenaBarrierHeightBlocks > 128) {
+            throw new IllegalArgumentException(
+                "arena-barrier-height-blocks must be between 3 and 128"
+            );
+        }
         requireFiniteRange(vigilanteBossHealth, 1.0, 1024.0, "vigilante-boss-health");
         requireFiniteRange(vigilanteBossDamage, 0.1, 2048.0, "vigilante-boss-damage");
         requireFiniteRange(vigilanteBossArmor, 0.0, 30.0, "vigilante-boss-armor");
@@ -100,6 +106,7 @@ public record PluginSettings(
             decimal(values, "tyrant-range-blocks", 50.0),
             decimal(values, "follower-range-blocks", 50.0),
             decimal(values, "vigilante-arena-radius-blocks", 10.0),
+            integer(values, "arena-barrier-height-blocks", 12),
             decimal(values, "vigilante-boss-health", 80.0),
             decimal(values, "vigilante-boss-damage", 8.0),
             decimal(values, "vigilante-boss-armor", 10.0),

src/main/java/games/dmg/spigottyrant/RoleArenaBarrier.java

@@ -8,22 +8,27 @@ import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.block.data.BlockData;
 
-final class VigilanteArenaBarrier {
+final class RoleArenaBarrier {
     private final Map<Location, BlockData> replaced = new LinkedHashMap<>();
     private boolean built;
 
-    void build(World world, ArenaLocation center, double radius) {
+    void build(
+        World world,
+        ArenaLocation center,
+        double radius,
+        int wallHeight
+    ) {
         if (built) {
             return;
         }
         built = true;
         int samples = Math.max(64, (int) Math.ceil(2.0 * Math.PI * radius * 2.0));
-        int baseY = (int) Math.floor(center.y());
+        int baseY = (int) Math.floor(center.y()) - 1;
         for (int index = 0; index < samples; index++) {
             double angle = 2.0 * Math.PI * index / samples;
             int x = (int) Math.floor(center.x() + Math.cos(angle) * radius);
             int z = (int) Math.floor(center.z() + Math.sin(angle) * radius);
-            for (int y = baseY; y < baseY + 3; y++) {
+            for (int y = baseY; y < baseY + wallHeight; y++) {
                 Block block = world.getBlockAt(x, y, z);
                 Location location = block.getLocation();
                 if (replaced.containsKey(location) || !isAir(block.getType())) {

src/main/java/games/dmg/spigottyrant/RoleArenaController.java

@@ -26,6 +26,8 @@ import org.bukkit.event.entity.EntityDamageByEntityEvent;
 import org.bukkit.event.entity.EntityDeathEvent;
 import org.bukkit.event.entity.EntityTargetLivingEntityEvent;
 import org.bukkit.event.entity.PlayerDeathEvent;
+import org.bukkit.event.block.BlockBreakEvent;
+import org.bukkit.event.block.BlockPlaceEvent;
 import org.bukkit.event.player.PlayerJoinEvent;
 import org.bukkit.event.player.PlayerMoveEvent;
 import org.bukkit.event.player.PlayerQuitEvent;
@@ -42,7 +44,7 @@ public final class RoleArenaController implements Listener, Runnable {
         new VigilanteArenaSuccessionService();
     private final TyrantArenaSuccessionService tyrantSuccession =
         new TyrantArenaSuccessionService();
-    private final VigilanteArenaBarrier barrier = new VigilanteArenaBarrier();
+    private final RoleArenaBarrier barrier = new RoleArenaBarrier();
     private final Set<UUID> relocating = new HashSet<>();
     private UUID bossId;
     private UUID challengerId;
@@ -121,10 +123,13 @@ public final class RoleArenaController implements Listener, Runnable {
                 )) {
             if (challengerId != null) {
                 resetFight();
+            } else {
+                ArenaBossState.idle(
+                    boss, toBukkit(world, arena), settings.vigilanteBossHealth()
+                );
             }
-            boss.setTarget(null);
         } else {
-            boss.setTarget(challenger);
+            ArenaBossState.engage(boss, challenger);
         }
         for (Player player : world.getPlayers()) {
             enforcePosition(player, null, player.getLocation());
@@ -193,6 +198,24 @@ public final class RoleArenaController implements Listener, Runnable {
         }
     }
 
+    @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
+    public void onBlockPlace(BlockPlaceEvent event) {
+        if (protects(event.getBlock().getLocation())) {
+            event.setCancelled(true);
+            event.getPlayer().sendMessage(ChatColor.RED
+                + "Blocks cannot be changed during an arena fight.");
+        }
+    }
+
+    @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
+    public void onBlockBreak(BlockBreakEvent event) {
+        if (protects(event.getBlock().getLocation())) {
+            event.setCancelled(true);
+            event.getPlayer().sendMessage(ChatColor.RED
+                + "Blocks cannot be changed during an arena fight.");
+        }
+    }
+
     @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
     public void onCombust(EntityCombustEvent event) {
         if (event.getEntity().getUniqueId().equals(bossId)) {
@@ -274,12 +297,15 @@ public final class RoleArenaController implements Listener, Runnable {
             challengerId = player.getUniqueId();
             World world = server.getWorld(arena.worldName());
             if (world != null) {
-                barrier.build(world, arena, settings.vigilanteArenaRadiusBlocks());
+                barrier.build(
+                    world, arena, settings.vigilanteArenaRadiusBlocks(),
+                    settings.arenaBarrierHeightBlocks()
+                );
                 Zombie boss = boss(world);
                 if (boss != null) {
                     boss.setHealth(settings.vigilanteBossHealth());
                     boss.teleport(toBukkit(world, arena));
-                    boss.setTarget(player);
+                    ArenaBossState.engage(boss, player);
                 }
             }
             player.sendMessage(ChatColor.GOLD + "Defeat the arena boss to become "
@@ -312,9 +338,10 @@ public final class RoleArenaController implements Listener, Runnable {
         World world = server.getWorld(configured.orElseThrow().worldName());
         Zombie boss = world == null ? null : boss(world);
         if (boss != null && !boss.isDead()) {
-            boss.setHealth(settings.vigilanteBossHealth());
+            ArenaBossState.idle(
-            boss.teleport(toBukkit(world, configured.orElseThrow()));
+                boss, toBukkit(world, configured.orElseThrow()),
-            boss.setTarget(null);
+                settings.vigilanteBossHealth()
+            );
         } else {
             bossId = null;
         }
@@ -349,6 +376,7 @@ public final class RoleArenaController implements Listener, Runnable {
                 zombie.setCustomNameVisible(true);
                 zombie.setRemoveWhenFarAway(false);
                 zombie.setCanPickupItems(false);
+                zombie.setAI(false);
                 zombie.addScoreboardTag(BOSS_TAG);
                 setAttribute(zombie, Attribute.MAX_HEALTH, settings.vigilanteBossHealth());
                 setAttribute(zombie, Attribute.ATTACK_DAMAGE, settings.vigilanteBossDamage());
@@ -442,29 +470,46 @@ public final class RoleArenaController implements Listener, Runnable {
     }
 
     private void drawBoundary(World world, ArenaLocation arena, ArenaRole role) {
-        if (barrier.active()) {
-            return;
-        }
         double radius = settings.vigilanteArenaRadiusBlocks();
         Color color = boundaryColor(role);
         Particle.DustOptions dust = color == null
             ? null : new Particle.DustOptions(color, 1.25F);
-        for (int index = 0; index < 48; index++) {
+        int[] heightOffsets = boundaryHeightOffsets(
-            double angle = 2.0 * Math.PI * index / 48.0;
+            barrier.active(), settings.arenaBarrierHeightBlocks()
-            Location point = new Location(
+        );
-                world,
+        for (int heightOffset : heightOffsets) {
-                arena.x() + Math.cos(angle) * radius,
+            for (int index = 0; index < 48; index++) {
-                arena.y() + 1.0,
+                double angle = 2.0 * Math.PI * index / 48.0;
-                arena.z() + Math.sin(angle) * radius
+                Location point = new Location(
-            );
+                    world,
-            if (dust == null) {
+                    arena.x() + Math.cos(angle) * radius,
-                world.spawnParticle(Particle.END_ROD, point, 1, 0.0, 0.0, 0.0, 0.0);
+                    arena.y() + heightOffset,
-            } else {
+                    arena.z() + Math.sin(angle) * radius
-                world.spawnParticle(Particle.DUST, point, 1, 0.0, 0.0, 0.0, 0.0, dust);
+                );
+                if (dust == null) {
+                    world.spawnParticle(
+                        Particle.END_ROD, point, 1, 0.0, 0.0, 0.0, 0.0
+                    );
+                } else {
+                    world.spawnParticle(
+                        Particle.DUST, point, 1, 0.0, 0.0, 0.0, 0.0, dust
+                    );
+                }
             }
         }
     }
 
+    private boolean protects(Location location) {
+        Optional<ArenaLocation> configured = locations.location();
+        World world = location.getWorld();
+        return configured.isPresent() && world != null
+            && ArenaBuildProtection.isProtected(
+                barrier.active(), configured.orElseThrow(),
+                settings.vigilanteArenaRadiusBlocks(), world.getName(),
+                location.getX(), location.getY(), location.getZ()
+            );
+    }
+
     private boolean contains(ArenaLocation arena, Location location) {
         World world = location.getWorld();
         return world != null && ArenaGeometry.contains(
@@ -535,6 +580,18 @@ public final class RoleArenaController implements Listener, Runnable {
         }
     }
 
+    static int[] boundaryHeightOffsets(boolean fightActive, int wallHeight) {
+        if (!fightActive) {
+            return new int[] {1};
+        }
+        int count = (wallHeight - 2) / 3 + 1;
+        int[] offsets = new int[count];
+        for (int index = 0; index < count; index++) {
+            offsets[index] = 1 + index * 3;
+        }
+        return offsets;
+    }
+
     static Color boundaryColor(ArenaRole role) {
         if (role == null) {
             return null;

src/main/resources/config.yml

@@ -4,6 +4,7 @@ follower-range-blocks: 50
 
 # Shared Tyrant and Vigilante arena and boss
 vigilante-arena-radius-blocks: 10
+arena-barrier-height-blocks: 12
 vigilante-boss-health: 80
 vigilante-boss-damage: 8
 vigilante-boss-armor: 10

src/test/java/games/dmg/spigottyrant/ArenaBossStateTest.java

@@ -0,0 +1,35 @@
+package games.dmg.spigottyrant;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+import org.bukkit.entity.Zombie;
+import org.junit.jupiter.api.Test;
+
+final class ArenaBossStateTest {
+    @Test
+    void idleBossIsCenteredHealedUntargetedAndFrozen() {
+        Zombie boss = mock(Zombie.class);
+        Location center = mock(Location.class);
+
+        ArenaBossState.idle(boss, center, 80.0);
+
+        verify(boss).setAI(false);
+        verify(boss).setTarget(null);
+        verify(boss).setHealth(80.0);
+        verify(boss).teleport(center);
+    }
+
+    @Test
+    void challengerEntryEnablesBossAndSetsTarget() {
+        Zombie boss = mock(Zombie.class);
+        Player challenger = mock(Player.class);
+
+        ArenaBossState.engage(boss, challenger);
+
+        verify(boss).setAI(true);
+        verify(boss).setTarget(challenger);
+    }
+}

src/test/java/games/dmg/spigottyrant/ArenaBuildProtectionTest.java

@@ -0,0 +1,25 @@
+package games.dmg.spigottyrant;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+final class ArenaBuildProtectionTest {
+    private static final ArenaLocation CENTER = new ArenaLocation(
+        "world", 0.0, 64.0, 0.0, 0.0F, 0.0F
+    );
+
+    @Test
+    void protectsOnlyInsideConfiguredArenaDuringFight() {
+        assertTrue(ArenaBuildProtection.isProtected(
+            true, CENTER, 10.0, "world", 5.0, 70.0, 5.0
+        ));
+        assertFalse(ArenaBuildProtection.isProtected(
+            false, CENTER, 10.0, "world", 5.0, 70.0, 5.0
+        ));
+        assertFalse(ArenaBuildProtection.isProtected(
+            true, CENTER, 10.0, "world", 11.0, 70.0, 0.0
+        ));
+    }
+}

src/test/java/games/dmg/spigottyrant/DefaultConfigurationTest.java

@@ -21,6 +21,7 @@ final class DefaultConfigurationTest {
         assertEquals(50.0, settings.tyrantRangeBlocks());
         assertEquals(Duration.ofDays(7), settings.optOutDuration());
         assertEquals(Duration.ofMinutes(1), settings.roleMaintenanceInterval());
+        assertEquals(12, settings.arenaBarrierHeightBlocks());
         assertEquals("FISHING_ROD", settings.tamerItem().material());
     }
 

src/test/java/games/dmg/spigottyrant/PluginSettingsTest.java

@@ -24,6 +24,7 @@ final class PluginSettingsTest {
         assertEquals(Duration.ofMinutes(10), settings.fixerEffectDuration());
         assertEquals(Duration.ofHours(24), settings.rosterIntelligenceCooldown());
         assertEquals(10.0, settings.vigilanteArenaRadiusBlocks());
+        assertEquals(12, settings.arenaBarrierHeightBlocks());
         assertEquals(80.0, settings.vigilanteBossHealth());
         assertEquals(8.0, settings.vigilanteBossDamage());
         assertEquals(10.0, settings.vigilanteBossArmor());
@@ -84,6 +85,10 @@ final class PluginSettingsTest {
             IllegalArgumentException.class,
             () -> PluginSettings.from(Map.of("vigilante-arena-radius-blocks", 0))
         );
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> PluginSettings.from(Map.of("arena-barrier-height-blocks", 2))
+        );
         assertThrows(
             IllegalArgumentException.class,
             () -> PluginSettings.from(Map.of("vigilante-boss-health", Double.NaN))

src/test/java/games/dmg/spigottyrant/RoleArenaBarrierTest.java

@@ -1,5 +1,6 @@
 package games.dmg.spigottyrant;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Mockito.atLeastOnce;
@@ -8,14 +9,16 @@ import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import java.util.List;
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.block.data.BlockData;
 import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
 
-final class VigilanteArenaBarrierTest {
+final class RoleArenaBarrierTest {
     private static final ArenaLocation CENTER = new ArenaLocation(
         "world", 0.0, 64.0, 0.0, 0.0F, 0.0F
     );
@@ -28,7 +31,7 @@ final class VigilanteArenaBarrierTest {
         when(solid.getLocation()).thenReturn(new Location(world, 1.0, 64.0, 0.0));
         when(solid.getType()).thenReturn(Material.CHEST);
 
-        new VigilanteArenaBarrier().build(world, CENTER, 10.0);
+        new RoleArenaBarrier().build(world, CENTER, 10.0, 12);
 
         verify(solid, never()).setType(Material.BARRIER, false);
     }
@@ -45,12 +48,30 @@ final class VigilanteArenaBarrierTest {
         when(air.getType()).thenReturn(Material.AIR);
         when(air.getBlockData()).thenReturn(original);
         when(original.clone()).thenReturn(snapshot);
-        VigilanteArenaBarrier barrier = new VigilanteArenaBarrier();
+        RoleArenaBarrier barrier = new RoleArenaBarrier();
 
-        barrier.build(world, CENTER, 10.0);
+        barrier.build(world, CENTER, 10.0, 12);
         barrier.clear();
 
         verify(air, atLeastOnce()).setType(Material.BARRIER, false);
         verify(air).setBlockData(snapshot, false);
     }
+
+    @Test
+    void wallExtendsOneBelowFloorForTwelveBlocks() {
+        World world = mock(World.class);
+        Block solid = mock(Block.class);
+        when(world.getBlockAt(anyInt(), anyInt(), anyInt())).thenReturn(solid);
+        when(solid.getLocation()).thenReturn(new Location(world, 1.0, 64.0, 0.0));
+        when(solid.getType()).thenReturn(Material.CHEST);
+        RoleArenaBarrier barrier = new RoleArenaBarrier();
+
+        barrier.build(world, CENTER, 10.0, 12);
+
+        ArgumentCaptor<Integer> y = ArgumentCaptor.forClass(Integer.class);
+        verify(world, atLeastOnce()).getBlockAt(anyInt(), y.capture(), anyInt());
+        List<Integer> values = y.getAllValues();
+        assertEquals(63, values.stream().mapToInt(Integer::intValue).min().orElseThrow());
+        assertEquals(74, values.stream().mapToInt(Integer::intValue).max().orElseThrow());
+    }
 }

src/test/java/games/dmg/spigottyrant/RoleArenaControllerTest.java

@@ -1,6 +1,7 @@
 package games.dmg.spigottyrant;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.mockito.ArgumentMatchers.contains;
 import static org.mockito.Mockito.mock;
@@ -29,6 +30,12 @@ final class RoleArenaControllerTest {
         assertEquals(Color.RED, RoleArenaController.boundaryColor(ArenaRole.TYRANT));
         assertEquals(Color.BLUE, RoleArenaController.boundaryColor(ArenaRole.VIGILANTE));
         assertNull(RoleArenaController.boundaryColor(null));
+        assertArrayEquals(
+            new int[] {1}, RoleArenaController.boundaryHeightOffsets(false, 12)
+        );
+        assertArrayEquals(
+            new int[] {1, 4, 7, 10}, RoleArenaController.boundaryHeightOffsets(true, 12)
+        );
     }
 
     @Test