Add a regression test for searching another player's library

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: liamiak1

forge-gui-desktop/src/test/java/forge/game/ability/effects/SearchOwnLibraryTest.java

@@ -0,0 +1,98 @@
+package forge.game.ability.effects;
+
+import org.testng.annotations.Test;
+
+import forge.ai.AITest;
+import forge.game.Game;
+import forge.game.GameObject;
+import forge.game.ability.AbilityUtils;
+import forge.game.card.Card;
+import forge.game.phase.PhaseType;
+import forge.game.player.Player;
+import forge.game.spellability.SpellAbility;
+import forge.game.zone.ZoneType;
+
+import static junit.framework.Assert.assertEquals;
+
+/**
+ * Opposition Agent applies only while an opponent searches <i>their own</i> library, so searching
+ * someone else's must not hand what is found to the Agent's controller.
+ */
+public class SearchOwnLibraryTest extends AITest {
+
+    private Game game;
+    private Player me; // controls the Agent in every case below
+    private Player opp;
+
+    @Test
+    public void agentAppliesOnlyWhenAnOpponentSearchesTheirOwnLibrary() {
+        // "search target opponent's library" retargets player, leaving me the one searching
+        Card ring = newGame("Sol Ring", "Mountain");
+        addCards("Island", 6, me);
+        cast("Acquire", me, opp);
+        assertEquals("my own Acquire must still fetch for me", ZoneType.Battlefield, zoneOf(ring));
+
+        // "search its controller's library" names the victim, but I am still the one looking.
+        // Sowing Salt exiles either way, so the tell is whether the Agent claimed what was found.
+        newGame("Bojuka Bog", "Mountain");
+        addCards("Mountain", 6, me);
+        cast("Sowing Salt", me, addCard("Bojuka Bog", opp));
+        assertEquals("Sowing Salt must not feed my own Agent", 0, cardsTheAgentTook());
+
+        // "target player searches their library": I cast it, but the Chooser makes them the
+        // searcher, so it is still their own search and the Agent takes what they find
+        Card forest = newGame("Forest", "Sol Ring");
+        addCards("Forest", 6, me);
+        cast("Fertilid's Favor", me, opp);
+        assertEquals("a search I handed to an opponent is still their own", ZoneType.Exile,
+                zoneOf(forest));
+
+        // and the case the card is for: an opponent tutoring out of their own library
+        Card prize = newGame("Sol Ring", "Mountain");
+        addCards("Swamp", 6, opp);
+        cast("Diabolic Tutor", opp, null);
+        assertEquals("their own tutor is still exiled by the Agent", ZoneType.Exile, zoneOf(prize));
+    }
+
+    /** Fresh game where I control the Agent and opp's library holds the prize plus filler. */
+    private Card newGame(String prize, String filler) {
+        game = initAndCreateGame();
+        me = game.getPlayers().get(0);
+        opp = game.getPlayers().get(1);
+        addCard("Opposition Agent", me);
+        Card c = addCardToZone(prize, opp, ZoneType.Library);
+        for (int i = 0; i < 4; i++) {
+            addCardToZone(filler, opp, ZoneType.Library);
+        }
+        return c;
+    }
+
+    /** Casts and resolves {@code name} from {@code p}'s hand, at {@code target} if there is one. */
+    private void cast(String name, Player p, GameObject target) {
+        game.getPhaseHandler().devModeSet(PhaseType.MAIN1, p);
+        game.getAction().checkStateEffects(true);
+        SpellAbility sa = addCardToZone(name, p, ZoneType.Hand).getFirstSpellAbility();
+        sa.setActivatingPlayer(p);
+        sa.resetTargets();
+        if (target != null) {
+            sa.getTargets().add(target);
+        }
+        AbilityUtils.resolve(sa);
+        game.getAction().checkStateEffects(true);
+    }
+
+    private ZoneType zoneOf(Card c) {
+        return game.getCardState(c, c).getZone().getZoneType();
+    }
+
+    /** How many exiled cards the Agent claimed - its replacement is what grants me permission. */
+    private int cardsTheAgentTook() {
+        int taken = 0;
+        for (Card c : opp.getCardsIn(ZoneType.Exile)) {
+            if (!c.mayPlay(me).isEmpty()) {
+                taken++;
+            }
+        }
+        return taken;
+    }
+}