Test framework improves (Monte Carlo AI):

* Added support to test Monte Carlo AI (CardTestPlayerBaseWithMonteCarloAIHelps - any aiXXX commands);
* Added Quick Start button to test Monte Carlo AI games (MCTS);

Mage.Tests/src/test/java/org/mage/test/cards/requirement/BecomeBlockTriggersMonteCarloAITest.java

@@ -0,0 +1,42 @@
+package org.mage.test.cards.requirement;
+
+import mage.constants.PhaseStep;
+import mage.constants.Zone;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBaseWithMonteCarloAIHelps;
+
+/**
+ * @author JayDi85
+ */
+public class BecomeBlockTriggersMonteCarloAITest extends CardTestPlayerBaseWithMonteCarloAIHelps {
+
+    // continue from BecomeBlockTriggersTest
+    @Test
+    public void test_AI_CantBlockAgain() {
+        // Monte Carlo bug: Triggered ability triggered twice (should be once), see https://github.com/magefree/mage/issues/6367
+
+        removeAllCardsFromHand(playerA);
+        removeAllCardsFromHand(playerB);
+
+        // All creatures able to block Nessian Boar do so.
+        // Whenever Nessian Boar becomes blocked by a creature, that creature’s controller draws a card.
+        addCard(Zone.BATTLEFIELD, playerA, "Nessian Boar", 1);
+        //
+        addCard(Zone.BATTLEFIELD, playerB, "Balduvian Bears", 1);
+
+        // auto-block by requirement effect
+        attack(1, playerA, "Nessian Boar");
+        // AI can't block same creature twice
+        aiPlayStep(1, PhaseStep.DECLARE_BLOCKERS, playerB);
+
+        setStopAt(1, PhaseStep.END_TURN);
+        setStrictChooseMode(true);
+        execute();
+        assertAllCommandsUsed();
+
+        assertGraveyardCount(playerA, 0);
+        assertGraveyardCount(playerB, 1);
+        assertHandCount(playerA, 0);
+        assertHandCount(playerB, 1);
+    }
+}

Mage.Tests/src/test/java/org/mage/test/player/TestComputerPlayerMonteCarlo.java

@@ -0,0 +1,73 @@
+package org.mage.test.player;
+
+import mage.MageObject;
+import mage.abilities.ActivatedAbility;
+import mage.abilities.SpellAbility;
+import mage.constants.Outcome;
+import mage.constants.RangeOfInfluence;
+import mage.game.Game;
+import mage.player.ai.ComputerPlayerMCTS;
+import mage.target.Target;
+
+import java.util.LinkedHashMap;
+import java.util.UUID;
+
+/**
+ * @author JayDi85
+ */
+
+// mock class to override AI logic in tests
+public class TestComputerPlayerMonteCarlo extends ComputerPlayerMCTS {
+
+    private TestPlayer testPlayerLink;
+
+    public TestComputerPlayerMonteCarlo(String name, RangeOfInfluence range, int skill) {
+        super(name, range, skill);
+    }
+
+    public void setTestPlayerLink(TestPlayer testPlayerLink) {
+        this.testPlayerLink = testPlayerLink;
+    }
+
+    @Override
+    public SpellAbility chooseSpellAbilityForCast(SpellAbility ability, Game game, boolean noMana) {
+        // copy-paste for TestComputerXXX
+
+        // workaround to cast fused cards in tests by it's NAMES (Wear, Tear, Wear // Tear)
+        // reason: TestPlayer uses outer computerPlayer to cast, not TestPlayer
+        switch (ability.getSpellAbilityType()) {
+            case SPLIT:
+            case SPLIT_FUSED:
+            case SPLIT_AFTERMATH:
+                if (!this.testPlayerLink.getChoices().isEmpty()) {
+                    MageObject object = game.getObject(ability.getSourceId());
+                    if (object != null) {
+                        LinkedHashMap<UUID, ActivatedAbility> useableAbilities = getSpellAbilities(playerId, object, game.getState().getZone(object.getId()), game);
+
+                        // left, right or fused cast
+                        for (String choose : this.testPlayerLink.getChoices()) {
+                            for (ActivatedAbility activatedAbility : useableAbilities.values()) {
+                                if (activatedAbility instanceof SpellAbility) {
+                                    if (((SpellAbility) activatedAbility).getCardName().equals(choose)) {
+                                        return (SpellAbility) activatedAbility;
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+        }
+
+        // default implementation by AI
+        return super.chooseSpellAbilityForCast(ability, game, noMana);
+    }
+
+    @Override
+    public boolean choose(Outcome outcome, Target target, UUID sourceId, Game game) {
+        // copy-paste for TestComputerXXX
+
+        // workaround for discard spells
+        // reason: TestPlayer uses outer computerPlayer to discard but inner code uses choose
+        return testPlayerLink.choose(outcome, target, sourceId, game);
+    }
+}

Mage.Tests/src/test/java/org/mage/test/serverside/base/CardTestPlayerBaseWithMonteCarloAIHelps.java

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+package org.mage.test.serverside.base;
+
+import mage.constants.RangeOfInfluence;
+import org.mage.test.player.TestComputerPlayerMonteCarlo;
+import org.mage.test.player.TestPlayer;
+
+/**
+ * Base class but with Monte Carlo computer player to test single AI commands (it's different from full AI simulation from CardTestPlayerBaseAI):
+ * 1. AI don't play normal priorities (you must use ai*** commands to play it);
+ * 2. AI will choose in non strict mode (it's simulated ComputerPlayerMCTS, not simple ComputerPlayer from basic tests)
+ *
+ * @author JayDi85
+ */
+public abstract class CardTestPlayerBaseWithMonteCarloAIHelps extends CardTestPlayerBase {
+
+    @Override
+    protected TestPlayer createPlayer(String name, RangeOfInfluence rangeOfInfluence) {
+        TestPlayer testPlayer = new TestPlayer(new TestComputerPlayerMonteCarlo(name, RangeOfInfluence.ONE, 6));
+        testPlayer.setAIPlayer(false); // AI can't play it by itself, use AI commands
+        return testPlayer;
+    }
+}