feat(assassin): add stealth and double jump

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

@@ -0,0 +1,60 @@
+package games.dmg.spigottyrant;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.Test;
+
+final class AbilityReadinessServiceTest {
+    private static final Instant NOW = Instant.parse("2026-08-14T12:00:00Z");
+    private final AbilityReadinessService service = new AbilityReadinessService();
+
+    @Test
+    void successfulCooldownActivationConsumesItemAndRefreshRestoresIt() {
+        PlayerState ready = player(
+            TyrantClass.ASSASSIN, Map.of(), Set.of(Ability.ASSASSIN_INVISIBILITY)
+        );
+
+        PlayerState used = service.consume(
+            ready, Ability.ASSASSIN_INVISIBILITY, NOW, Duration.ofHours(1)
+        );
+        PlayerState refreshed = service.refresh(used, NOW.plus(Duration.ofHours(1)));
+
+        assertEquals(Set.of(), used.readyAbilityItems());
+        assertEquals(NOW.plus(Duration.ofHours(1)),
+            used.cooldownEnds().get(Ability.ASSASSIN_INVISIBILITY));
+        assertEquals(Set.of(Ability.ASSASSIN_INVISIBILITY),
+            refreshed.readyAbilityItems());
+        assertEquals(Map.of(), refreshed.cooldownEnds());
+    }
+
+    @Test
+    void tamerItemRemainsReadyWithoutCooldown() {
+        PlayerState tamer = player(
+            TyrantClass.TAMER, Map.of(), Set.of(Ability.TAMER_CAPTURE)
+        );
+
+        PlayerState after = service.consume(
+            tamer, Ability.TAMER_CAPTURE, NOW, Duration.ZERO
+        );
+
+        assertEquals(tamer, after);
+    }
+
+    private static PlayerState player(
+        TyrantClass tyrantClass,
+        Map<Ability, Instant> cooldowns,
+        Set<Ability> ready
+    ) {
+        return new PlayerState(
+            UUID.fromString("11111111-1111-1111-1111-111111111111"), "Player",
+            Optional.empty(), Optional.empty(), tyrantClass, Optional.empty(),
+            cooldowns, ready, java.util.List.of()
+        );
+    }
+}

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

@@ -0,0 +1,60 @@
+package games.dmg.spigottyrant;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.time.Instant;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.UUID;
+import org.junit.jupiter.api.Test;
+
+final class AssassinAbilityServiceTest {
+    private static final Instant NOW = Instant.parse("2026-08-14T12:00:00Z");
+    private final PluginSettings settings = PluginSettings.from(Map.of());
+    private final AssassinAbilityService service = new AssassinAbilityService(
+        new AbilityReadinessService(), settings
+    );
+
+    @Test
+    void invisibilityConsumesItemAndDoublesDurationNearTyrant() {
+        PlayerState ready = assassin(Set.of(Ability.ASSASSIN_INVISIBILITY), Map.of());
+
+        AbilityUseResult normal = service.activateInvisibility(ready, NOW, false);
+        AbilityUseResult near = service.activateInvisibility(ready, NOW, true);
+
+        assertEquals(AbilityUseStatus.ACTIVATED, normal.status());
+        assertEquals(NOW.plusSeconds(600), normal.player().cooldownEnds()
+            .get(Ability.ASSASSIN_INVISIBILITY_ACTIVE));
+        assertEquals(NOW.plusSeconds(1200), near.player().cooldownEnds()
+            .get(Ability.ASSASSIN_INVISIBILITY_ACTIVE));
+        assertEquals(NOW.plusSeconds(3600), normal.player().cooldownEnds()
+            .get(Ability.ASSASSIN_INVISIBILITY));
+        assertEquals(Set.of(), normal.player().readyAbilityItems());
+    }
+
+    @Test
+    void doubleJumpAddsSpeedWeaknessAndSixtySecondCooldown() {
+        PlayerState assassin = assassin(Set.of(), Map.of());
+
+        AbilityUseResult result = service.doubleJump(assassin, NOW);
+        AbilityUseResult blocked = service.doubleJump(result.player(), NOW.plusSeconds(30));
+
+        assertEquals(AbilityUseStatus.ACTIVATED, result.status());
+        assertEquals(NOW.plusSeconds(60), result.player().cooldownEnds()
+            .get(Ability.ASSASSIN_DOUBLE_JUMP));
+        assertEquals(NOW.plusSeconds(15), result.player().cooldownEnds()
+            .get(Ability.ASSASSIN_SPEED_ACTIVE));
+        assertEquals(NOW.plusSeconds(20), result.player().cooldownEnds()
+            .get(Ability.ASSASSIN_WEAKNESS_ACTIVE));
+        assertEquals(AbilityUseStatus.COOLDOWN, blocked.status());
+    }
+
+    private static PlayerState assassin(Set<Ability> ready, Map<Ability, Instant> cooldowns) {
+        return new PlayerState(
+            UUID.fromString("11111111-1111-1111-1111-111111111111"), "Assassin",
+            Optional.empty(), Optional.empty(), TyrantClass.ASSASSIN, Optional.empty(),
+            cooldowns, ready, java.util.List.of()
+        );
+    }
+}

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

@@ -46,6 +46,8 @@ final class ClassAssignmentServiceTest {
         assertEquals(ClassAssignmentStatus.ASSIGNED, vigilanteResult.status());
         assertEquals(TyrantClass.ASSASSIN,
             vigilanteResult.players().get(VIGILANTE).tyrantClass());
+        assertEquals(Set.of(Ability.ASSASSIN_INVISIBILITY),
+            vigilanteResult.players().get(VIGILANTE).readyAbilityItems());
         assertEquals(ClassAssignmentStatus.ASSIGNED, followerResult.status());
         assertEquals(TyrantClass.NONE,
             followerResult.players().get(VIGILANTE).tyrantClass());