fix and test [C21] Incarnation Technique

Incarnation Technique was not processing trigger properly inbetween the mill and return.

part of #13601

Mage.Sets/src/mage/cards/i/IncarnationTechnique.java

@@ -2,6 +2,7 @@ package mage.cards.i;
 
 import mage.abilities.Ability;
 import mage.abilities.effects.OneShotEffect;
+import mage.abilities.effects.common.MillCardsControllerEffect;
 import mage.abilities.keyword.DemonstrateAbility;
 import mage.cards.Card;
 import mage.cards.CardImpl;
@@ -29,6 +30,7 @@ public final class IncarnationTechnique extends CardImpl {
         this.addAbility(new DemonstrateAbility());
 
         // Mill five cards, then return a creature card from your graveyard to the battlefield.
+        this.getSpellAbility().addEffect(new MillCardsControllerEffect(5).concatBy(", then"));
         this.getSpellAbility().addEffect(new IncarnationTechniqueEffect());
     }
 
@@ -46,7 +48,7 @@ class IncarnationTechniqueEffect extends OneShotEffect {
 
     IncarnationTechniqueEffect() {
         super(Outcome.Benefit);
-        staticText = "mill five cards, then return a creature card from your graveyard to the battlefield";
+        staticText = "return a creature card from your graveyard to the battlefield";
     }
 
     private IncarnationTechniqueEffect(final IncarnationTechniqueEffect effect) {
@@ -64,7 +66,6 @@ class IncarnationTechniqueEffect extends OneShotEffect {
         if (player == null) {
             return false;
         }
-        player.millCards(5, source, game);
         TargetCard target = new TargetCardInYourGraveyard(StaticFilters.FILTER_CARD_CREATURE_YOUR_GRAVEYARD);
         target.withNotTarget(true);
         if (!target.canChoose(source.getControllerId(), source, game)) {

Mage.Tests/src/test/java/org/mage/test/cards/single/c21/IncarnationTechniqueTest.java

@@ -0,0 +1,125 @@
+package org.mage.test.cards.single.c21;
+
+import mage.constants.PhaseStep;
+import mage.constants.Zone;
+import mage.counters.CounterType;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBase;
+
+/**
+ * @author Susucr
+ */
+
+public class IncarnationTechniqueTest extends CardTestPlayerBase {
+
+    /**
+     * {@link mage.cards.i.IncarnationTechnique Incarnation Technique} {4}{B}
+     * Sorcery
+     * Demonstrate (When you cast this spell, you may copy it. If you do, choose an opponent to also copy it.)
+     * Mill five cards, then return a creature card from your graveyard to the battlefield.
+     */
+    private static final String technique = "Incarnation Technique";
+
+    private static final String myr = "Omega Myr"; // vanilla 1/2
+
+    /**
+     * Emrakul, the Aeons Torn {15}
+     * Legendary Creature — Eldrazi
+     * This spell can’t be countered.
+     * When you cast this spell, take an extra turn after this one.
+     * Flying, protection from spells that are one or more colors, annihilator 6
+     * When Emrakul is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.
+     * 15/15
+     */
+    private static final String emrakul = "Emrakul, the Aeons Torn";
+
+    /**
+     * Cosi's Trickster {U}
+     * Creature — Merfolk Wizard
+     * Whenever an opponent shuffles their library, you may put a +1/+1 counter on this creature.
+     * 1/1
+     */
+    private static final String trickster = "Cosi's Trickster";
+
+    @Test
+    public void testNoCreatureToReturn() {
+        setStrictChooseMode(true);
+        skipInitShuffling();
+
+        addCard(Zone.HAND, playerA, technique);
+        addCard(Zone.BATTLEFIELD, playerA, "Swamp", 5);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, technique);
+        setChoice(playerA, true); // yes to demonstrate
+        setChoice(playerA, playerB.getName()); // choosing B for demonstrate copy
+
+        setStopAt(1, PhaseStep.END_COMBAT);
+        execute();
+
+        assertGraveyardCount(playerA, 5 * 2 + 1);
+        assertGraveyardCount(playerB, 5);
+    }
+
+    @Test
+    public void testCreatureInGraveyard() {
+        setStrictChooseMode(true);
+        skipInitShuffling();
+
+        addCard(Zone.HAND, playerA, technique);
+        addCard(Zone.GRAVEYARD, playerA, myr);
+        addCard(Zone.BATTLEFIELD, playerA, "Swamp", 5);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, technique);
+        setChoice(playerA, false); // no to demonstrate
+        setChoice(playerA, myr); // returned creature
+
+        setStopAt(1, PhaseStep.END_COMBAT);
+        execute();
+
+        assertPermanentCount(playerA, myr, 1);
+        assertGraveyardCount(playerA, 5 + 1);
+    }
+
+    @Test
+    public void testCreatureMilled() {
+        setStrictChooseMode(true);
+        skipInitShuffling();
+
+        addCard(Zone.HAND, playerA, technique);
+        addCard(Zone.LIBRARY, playerA, myr);
+        addCard(Zone.BATTLEFIELD, playerA, "Swamp", 5);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, technique);
+        setChoice(playerA, false); // no to demonstrate
+        setChoice(playerA, myr); // returned creature
+
+        setStopAt(1, PhaseStep.END_COMBAT);
+        execute();
+
+        assertPermanentCount(playerA, myr, 1);
+        assertGraveyardCount(playerA, 4 + 1);
+    }
+
+    @Test
+    public void testEmrakul() {
+        setStrictChooseMode(true);
+        skipInitShuffling();
+
+        addCard(Zone.HAND, playerA, technique);
+        addCard(Zone.BATTLEFIELD, playerB, trickster);
+        addCard(Zone.LIBRARY, playerA, emrakul);
+        addCard(Zone.BATTLEFIELD, playerA, "Swamp", 5);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, technique);
+        setChoice(playerA, false); // no to demonstrate
+        setChoice(playerA, emrakul); // returned creature
+        setChoice(playerB, true); // yes to Cosi's Trickster may trigger
+
+        setStopAt(1, PhaseStep.END_COMBAT);
+        execute();
+
+        assertPermanentCount(playerA, emrakul, 1);
+        assertGraveyardCount(playerA, 0);
+        assertCounterCount(playerB, trickster, CounterType.P1P1, 1);
+    }
+}