Add fuse test. Also made some modification to allow the test to work

build.gradle.kts

@@ -87,7 +87,7 @@ allprojects {
         compileOnly(kotlin("stdlib"))
 
         // Test dependency
-        testImplementation(platform("org.junit:junit-bom:5.9.1"))
+        testImplementation(platform("org.junit:junit-bom:5.11.3"))
         testImplementation("org.junit.jupiter:junit-jupiter")
     }
 

nms/v1_21R1/src/main/kotlin/xyz/alexcrea/cuanvil/dependency/gui/version/v1_21R1_ExternGuiTester.kt

@@ -7,10 +7,28 @@ import xyz.alexcrea.cuanvil.dependency.gui.ExternGuiTester
 class v1_21R1_ExternGuiTester: ExternGuiTester {
     override val wesjdAnvilGuiName = "Wrapper1_21_R1"
 
+    var tested = false;
+    var possible = false;
+
     override fun getContainerClass(view: InventoryView): Class<Any>? {
+        // In case we are in a test environment
+        if(!tested) testClassExist()
+        if(!possible) return null
+
         if(view !is CraftInventoryView<*, *>) return null
         val container = view.handle
 
         return container.javaClass
     }
+
+    fun testClassExist(){
+        tested = true;
+        try {
+            Class.forName("org.bukkit.craftbukkit.inventory.CraftInventoryView")
+            possible = true
+        } catch (e: ClassNotFoundException){
+            possible = false
+        }
+    }
+
 }

src/main/java/xyz/alexcrea/cuanvil/enchant/bulk/BukkitEnchantBulkOperation.java

@@ -29,7 +29,8 @@ public class BukkitEnchantBulkOperation implements BulkGetEnchantOperation, Bulk
     @Override
     public void bulkClear(@NotNull ItemStack item) {
         if (item.getType() != Material.ENCHANTED_BOOK) {
-            item.getEnchantments().forEach((enchantment, leve) ->
+
+            item.getEnchantments().forEach((enchantment, level) ->
                     item.removeEnchantment(enchantment)
             );
         }
@@ -43,5 +44,6 @@ public class BukkitEnchantBulkOperation implements BulkGetEnchantOperation, Bulk
                     bookMeta.removeStoredEnchant(enchantment)
             );
         }
+
     }
 }

src/main/kotlin/xyz/alexcrea/cuanvil/dependency/DependencyManager.kt

@@ -2,6 +2,7 @@ package xyz.alexcrea.cuanvil.dependency
 
 import io.delilaheve.CustomAnvil
 import org.bukkit.Bukkit
+import org.bukkit.entity.HumanEntity
 import org.bukkit.event.inventory.InventoryClickEvent
 import org.bukkit.event.inventory.PrepareAnvilEvent
 import org.bukkit.inventory.AnvilInventory
@@ -91,11 +92,11 @@ object DependencyManager {
 
     }
 
-    fun tryEventPreAnvilBypass(event: PrepareAnvilEvent): Boolean {
+    fun tryEventPreAnvilBypass(event: PrepareAnvilEvent, player: HumanEntity): Boolean {
         var bypass = false
 
         // Test if disenchantment used special prepare anvil
-        if(disenchantmentCompatibility?.testPrepareAnvil(event) == true) bypass = true
+        if(disenchantmentCompatibility?.testPrepareAnvil(event, player) == true) bypass = true
 
         // Test excellent enchantments used special prepare anvil
         if(!bypass && (excellentEnchantsCompatibility?.testPrepareAnvil(event) == true)) bypass = true

src/main/kotlin/xyz/alexcrea/cuanvil/dependency/DisenchantmentDependency.kt

@@ -5,6 +5,7 @@ import cz.kominekjan.disenchantment.events.DisenchantEvent
 import cz.kominekjan.disenchantment.events.ShatterClickEvent
 import cz.kominekjan.disenchantment.events.ShatterEvent
 import io.delilaheve.CustomAnvil
+import org.bukkit.entity.HumanEntity
 import org.bukkit.event.inventory.InventoryClickEvent
 import org.bukkit.event.inventory.PrepareAnvilEvent
 import org.bukkit.inventory.AnvilInventory
@@ -70,7 +71,7 @@ class DisenchantmentDependency {
 
     }
 
-    fun testPrepareAnvil(event: PrepareAnvilEvent): Boolean {
+    fun testPrepareAnvil(event: PrepareAnvilEvent, player: HumanEntity): Boolean {
         val previousResult = event.result
         event.result = null
 
@@ -79,14 +80,14 @@ class DisenchantmentDependency {
 
         if(event.result != null) {
             CustomAnvil.log("Detected pre anvil item extract bypass.")
-            AnvilXpUtil.setAnvilInvXp(event.inventory, event.view, event.inventory.repairCost)
+            AnvilXpUtil.setAnvilInvXp(event.inventory, event.view, player, event.inventory.repairCost)
             return true
         }
 
         splitEvent.onDisenchantmentEvent(event)
         if(event.result != null) {
             CustomAnvil.log("Detected pre anvil split enchant bypass.")
-            AnvilXpUtil.setAnvilInvXp(event.inventory, event.view, event.inventory.repairCost)
+            AnvilXpUtil.setAnvilInvXp(event.inventory, event.view, player, event.inventory.repairCost)
             return true
         }
 

src/main/kotlin/xyz/alexcrea/cuanvil/listener/PrepareAnvilListener.kt

@@ -11,11 +11,13 @@ import io.delilaheve.util.ItemUtil.setEnchantmentsUnsafe
 import io.delilaheve.util.ItemUtil.unitRepair
 import org.bukkit.ChatColor
 import org.bukkit.entity.HumanEntity
+import org.bukkit.entity.Player
 import org.bukkit.event.EventHandler
 import org.bukkit.event.EventPriority
 import org.bukkit.event.Listener
 import org.bukkit.event.inventory.PrepareAnvilEvent
 import org.bukkit.inventory.AnvilInventory
+import org.bukkit.inventory.InventoryView
 import org.bukkit.inventory.ItemStack
 import xyz.alexcrea.cuanvil.dependency.DependencyManager
 import xyz.alexcrea.cuanvil.util.AnvilColorUtil
@@ -41,19 +43,20 @@ class PrepareAnvilListener : Listener {
      */
     @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
     fun anvilCombineCheck(event: PrepareAnvilEvent) {
+        // Should find player
+        val player: HumanEntity = event.viewers.first()
+
         // Test if the event should bypass custom anvil.
-        if(DependencyManager.tryEventPreAnvilBypass(event)) return
+        if(DependencyManager.tryEventPreAnvilBypass(event, player)) return
 
         val inventory = event.inventory
         val first = inventory.getItem(ANVIL_INPUT_LEFT) ?: return
         val second = inventory.getItem(ANVIL_INPUT_RIGHT)
 
-        // Should find player
-        val player = event.view.player
         if (!player.hasPermission(CustomAnvil.affectedByPluginPermission)) return
 
         // Test custom recipe
-        if(testCustomRecipe(event, inventory, first, second)) return
+        if(testCustomRecipe(event, inventory, player, first, second)) return
 
         // Test rename lonely item
         if(second == null) {
@@ -75,7 +78,9 @@ class PrepareAnvilListener : Listener {
 
     }
 
-    private fun testCustomRecipe(event: PrepareAnvilEvent, inventory: AnvilInventory, first: ItemStack, second: ItemStack?): Boolean {
+    private fun testCustomRecipe(event: PrepareAnvilEvent, inventory: AnvilInventory,
+                                 player: HumanEntity,
+                                 first: ItemStack, second: ItemStack?): Boolean {
         val recipe = CustomRecipeUtil.getCustomRecipe(first, second)
         CustomAnvil.verboseLog("custom recipe not null? ${recipe != null}")
         if(recipe == null) return false
@@ -87,7 +92,7 @@ class PrepareAnvilListener : Listener {
 
         event.result = resultItem
         DependencyManager.treatAnvilResult(event, resultItem)
-        AnvilXpUtil.setAnvilInvXp(inventory, event.view, recipe.xpCostPerCraft * amount, true)
+        AnvilXpUtil.setAnvilInvXp(inventory, event.view, player, recipe.xpCostPerCraft * amount, true)
 
         return true
     }
@@ -109,7 +114,7 @@ class PrepareAnvilListener : Listener {
 
         anvilCost += AnvilXpUtil.calculatePenalty(first, null, resultItem)
 
-        AnvilXpUtil.setAnvilInvXp(inventory, event.view, anvilCost)
+        AnvilXpUtil.setAnvilInvXp(inventory, event.view, player, anvilCost)
     }
 
     private fun handleRename(resultItem: ItemStack, inventory: AnvilInventory, player: HumanEntity): Int {
@@ -177,7 +182,7 @@ class PrepareAnvilListener : Listener {
         event.result = resultItem
         DependencyManager.treatAnvilResult(event, resultItem)
 
-        AnvilXpUtil.setAnvilInvXp(inventory, event.view, anvilCost)
+        AnvilXpUtil.setAnvilInvXp(inventory, event.view, player, anvilCost)
     }
 
     private fun testUnitRepair(event: PrepareAnvilEvent, inventory: AnvilInventory, player: HumanEntity,
@@ -203,7 +208,7 @@ class PrepareAnvilListener : Listener {
         event.result = resultItem
         DependencyManager.treatAnvilResult(event, resultItem)
 
-        AnvilXpUtil.setAnvilInvXp(inventory, event.view, anvilCost)
+        AnvilXpUtil.setAnvilInvXp(inventory, event.view, player, anvilCost)
         return true
     }
 

src/main/kotlin/xyz/alexcrea/cuanvil/util/AnvilXpUtil.kt

@@ -6,6 +6,7 @@ import io.delilaheve.util.EnchantmentUtil.enchantmentName
 import io.delilaheve.util.ItemUtil.findEnchantments
 import io.delilaheve.util.ItemUtil.isEnchantedBook
 import org.bukkit.GameMode
+import org.bukkit.entity.HumanEntity
 import org.bukkit.entity.Player
 import org.bukkit.inventory.AnvilInventory
 import org.bukkit.inventory.InventoryView
@@ -25,6 +26,7 @@ object AnvilXpUtil {
     fun setAnvilInvXp(
         inventory: AnvilInventory,
         view: InventoryView,
+        player: HumanEntity,
         anvilCost: Int,
         ignoreRules: Boolean = false
     ) {
@@ -38,8 +40,6 @@ object AnvilXpUtil {
             anvilCost
         }
 
-        val player = view.player
-
         /* Because Minecraft likes to have the final say in the repair cost displayed
             * we need to wait for the event to end before overriding it, this ensures that
             * we have the final say in the process. */

src/test/java/io/delilaheve/CustomAnvilTests.java

@@ -1,44 +1,15 @@
 package io.delilaheve;
 
-import be.seeseemelk.mockbukkit.MockBukkit;
+import org.junit.jupiter.api.Assertions;
-import be.seeseemelk.mockbukkit.ServerMock;
-import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import xyz.alexcrea.cuanvil.DefaultCustomAnvilTest;
 
-public class CustomAnvilTests {
+public class CustomAnvilTests extends DefaultCustomAnvilTest {
-
-    private ServerMock server;
-
-    private CustomAnvil plugin;
-
-    @BeforeEach
-    public void setUp() {
-
-        // Start the mock server
-        server = MockBukkit.mock();
-
-        // Load your plugin
-        plugin = MockBukkit.load(CustomAnvil.class);
-
-
-
-    }
-
-
-    @AfterEach
-    public void tearDown() {
-        // Stop the mock server
-        MockBukkit.unmock();
-
-    }
-
 
     @Test
     public void simpleInitTest() {
-        // Continue initialization of the plugin
+        Assertions.assertNotNull(server);
-        server.getScheduler().performOneTick();
+        Assertions.assertNotNull(plugin);
-
     }
 
 }

src/test/java/xyz/alexcrea/cuanvil/DefaultCustomAnvilTest.java

@@ -0,0 +1,53 @@
+package xyz.alexcrea.cuanvil;
+
+import be.seeseemelk.mockbukkit.MockBukkit;
+import be.seeseemelk.mockbukkit.ServerMock;
+import io.delilaheve.CustomAnvil;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import xyz.alexcrea.cuanvil.config.ConfigHolder;
+import xyz.alexcrea.cuanvil.enchant.CAEnchantment;
+import xyz.alexcrea.cuanvil.enchant.CAEnchantmentRegistry;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class DefaultCustomAnvilTest {
+
+    protected ServerMock server;
+    protected CustomAnvil plugin;
+
+    @BeforeEach
+    public void setUp() {
+        // Start the mock server
+        server = MockBukkit.mock();
+        // Load your plugin
+        plugin = MockBukkit.load(CustomAnvil.class);
+        // Continue initialization of the plugin
+        server.getScheduler().performOneTick();
+    }
+
+    @AfterEach
+    public void tearDown() {
+        // Set config to null
+        ConfigHolder.DEFAULT_CONFIG = null;
+        ConfigHolder.ITEM_GROUP_HOLDER = null;
+        ConfigHolder.CONFLICT_HOLDER = null;
+        ConfigHolder.UNIT_REPAIR_HOLDER = null;
+        ConfigHolder.CUSTOM_RECIPE_HOLDER = null;
+        
+        // Stop the mock server
+        MockBukkit.unmock();
+
+        // Unregister enchantments
+        List<CAEnchantment> toUnregister = new ArrayList<>(
+                CAEnchantmentRegistry.getInstance().values()
+        );
+
+        for (CAEnchantment caEnchantment : toUnregister) {
+            CAEnchantmentRegistry.getInstance().unregister(caEnchantment);
+        }
+
+    }
+
+}

src/test/java/xyz/alexcrea/cuanvil/anvil/AnvilFuseTest.java

@@ -0,0 +1,81 @@
+package xyz.alexcrea.cuanvil.anvil;
+
+import be.seeseemelk.mockbukkit.entity.PlayerMock;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.AnvilInventory;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import xyz.alexcrea.cuanvil.DefaultCustomAnvilTest;
+import xyz.alexcrea.cuanvil.config.ConfigHolder;
+import xyz.alexcrea.cuanvil.util.AnvilFuseTestData;
+import xyz.alexcrea.cuanvil.util.AnvilFuseTestUtil;
+import xyz.alexcrea.cuanvil.util.CommonItemUtil;
+
+public class AnvilFuseTest extends DefaultCustomAnvilTest {
+
+    private AnvilInventory anvil;
+    private PlayerMock player;
+
+    @Override
+    @BeforeEach
+    public void setUp() {
+        super.setUp();
+        // Mock used player & open anvil
+        player = server.addPlayer();
+
+        Inventory anvil = server.createInventory(player, InventoryType.ANVIL);
+
+        this.anvil = (AnvilInventory) anvil;
+        player.openInventory(anvil);
+
+        ConfigHolder.DEFAULT_CONFIG.getConfig().set("debug_log", true);
+        ConfigHolder.DEFAULT_CONFIG.getConfig().set("debug_log_verbose", true);
+    }
+
+    @Test
+    public void mergeFuseTest(){
+        // Literally just test a sharpness 4 + sharpness 4
+        ItemStack sharpness4 = CommonItemUtil.sharpness(4);
+        ItemStack sharpness5 = CommonItemUtil.sharpness(5);
+
+        AnvilFuseTestData data = new AnvilFuseTestData(
+                sharpness4, sharpness4,
+                sharpness5
+                // TODO add expected price
+        );
+
+        AnvilFuseTestUtil.executeAnvilTest(anvil, player, data);
+    }
+
+    @Test
+    public void overFuseTest(){
+        // Test sharpness 4 + sharpness 5
+        ItemStack sharpness4 = CommonItemUtil.sharpness(4);
+        ItemStack sharpness5 = CommonItemUtil.sharpness(5);
+
+        AnvilFuseTestData data = new AnvilFuseTestData(
+                sharpness4, sharpness5,
+                sharpness5
+                // TODO add expected price
+        );
+
+        AnvilFuseTestUtil.executeAnvilTest(anvil, player, data);
+    }
+
+    @Test
+    public void underFuseTest(){
+        // test sharpness 5 + 4. Custom Anvil should not allow it to be as it result as the same item as left item
+        ItemStack sharpness4 = CommonItemUtil.sharpness(4);
+        ItemStack sharpness5 = CommonItemUtil.sharpness(5);
+
+        AnvilFuseTestData data = new AnvilFuseTestData(
+                sharpness5, sharpness4,
+                null
+        );
+
+        AnvilFuseTestUtil.executeAnvilTest(anvil, player, data);
+    }
+
+}

src/test/java/xyz/alexcrea/cuanvil/mock/AnvilViewMock.java

@@ -0,0 +1,76 @@
+package xyz.alexcrea.cuanvil.mock;
+
+import be.seeseemelk.mockbukkit.inventory.PlayerInventoryViewMock;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.inventory.AnvilInventory;
+import org.bukkit.inventory.view.AnvilView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+@SuppressWarnings({"removal"})
+public class AnvilViewMock extends PlayerInventoryViewMock implements AnvilView {
+
+    private @NotNull AnvilInventory top;
+
+    /**
+     * Constructs a new {@link PlayerInventoryViewMock} for the provided player, with the specified top inventory.
+     *
+     * @param player The player to create the view for.
+     * @param top    The top inventory.
+     */
+    public AnvilViewMock(@NotNull HumanEntity player, @NotNull AnvilInventory top) {
+        super(player, top);
+        this.top = top;
+    }
+
+    @Override
+    public @Nullable String getRenameText() {
+        return top.getRenameText();
+    }
+
+    @Override
+    public int getRepairItemCountCost() {
+        return top.getRepairCostAmount();
+    }
+
+    @Override
+    public int getRepairCost() {
+        return top.getRepairCost();
+    }
+
+    @Override
+    public int getMaximumRepairCost() {
+        return top.getMaximumRepairCost();
+    }
+
+    @Override
+    public void setRepairItemCountCost(int amount) {
+        top.setRepairCostAmount(amount);
+    }
+
+    @Override
+    public void setRepairCost(int cost) {
+        top.setRepairCost(cost);
+    }
+
+    @Override
+    public void setMaximumRepairCost(int levels) {
+        top.setMaximumRepairCost(levels);
+    }
+
+    @Override
+    public boolean bypassesEnchantmentLevelRestriction() {
+        throw new UnsupportedOperationException("Custom anvil was not think with this existing");
+    }
+
+    @Override
+    public void bypassEnchantmentLevelRestriction(boolean bypassEnchantmentLevelRestriction) {
+        throw new UnsupportedOperationException("Custom anvil was not think with this existing");
+    }
+
+    @Override
+    public @NotNull AnvilInventory getTopInventory() {
+        return top;
+    }
+
+}

src/test/java/xyz/alexcrea/cuanvil/mock/EnchantedItemStackMock.java

@@ -0,0 +1,56 @@
+package xyz.alexcrea.cuanvil.mock;
+
+import be.seeseemelk.mockbukkit.inventory.ItemStackMock;
+import com.google.common.collect.ImmutableMap;
+import org.bukkit.Material;
+import org.bukkit.enchantments.Enchantment;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Map;
+
+public class EnchantedItemStackMock extends ItemStackMock {
+
+    EnchantedItemStackMock(){}
+
+    public EnchantedItemStackMock(@NotNull Material type, int amount) {
+        super(type, amount);
+    }
+
+    public EnchantedItemStackMock(@NotNull Material type) {
+        this(type, 1);
+    }
+
+    public EnchantedItemStackMock(@NotNull ItemStack stack) throws IllegalArgumentException {
+        super(stack);
+    }
+
+    @Override
+    public int removeEnchantment(@NotNull Enchantment ench) {
+        int level = this.getEnchantmentLevel(ench);
+        this.getItemMeta().removeEnchant(ench);
+
+        return level;
+    }
+
+    @Override
+    public void removeEnchantments() {
+        this.getItemMeta().removeEnchantments();
+    }
+
+    // badly imitate paper (and I hope spigot) behavior and avoid concurrent modification exception
+    @Override
+    public @NotNull Map<Enchantment, Integer> getEnchantments() {
+        return ImmutableMap.copyOf(super.getEnchantments());
+    }
+
+    @Override
+    public @NotNull ItemStack clone() {
+        ItemStackMock clone = new EnchantedItemStackMock(this.getType());
+
+        clone.setAmount(this.getAmount());
+        clone.setDurability(this.getDurability());
+        clone.setItemMeta(this.hasItemMeta() ? this.getItemMeta().clone() : null);
+        return clone;
+    }
+}

src/test/java/xyz/alexcrea/cuanvil/util/AnvilFuseTestData.java

@@ -0,0 +1,39 @@
+package xyz.alexcrea.cuanvil.util;
+
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.Nullable;
+
+public record AnvilFuseTestData(
+        @Nullable ItemStack leftItem,
+        @Nullable ItemStack rightItem,
+        @Nullable ItemStack expectedResult,
+
+        @Nullable ItemStack expectedAfterLeftPlaced,
+        @Nullable ItemStack expectedAfterRightPlaced,
+
+        @Nullable Integer expectedPriceAfterLeftPlaced,
+        @Nullable Integer expectedPriceAfterRightPlaced,
+        @Nullable Integer expectedPriceAfterBothPlaced
+        ){
+
+    public AnvilFuseTestData(
+            @Nullable ItemStack leftItem,
+            @Nullable ItemStack rightItem,
+            @Nullable ItemStack expectedResult,
+            @Nullable Integer expectedPriceAfterBothPlaced
+    ){
+        this(leftItem, rightItem, expectedResult,
+                null, null, null, null,
+                expectedPriceAfterBothPlaced
+        );
+    }
+
+    public AnvilFuseTestData(
+            @Nullable ItemStack leftItem,
+            @Nullable ItemStack rightItem,
+            @Nullable ItemStack expectedResult
+    ){
+        this(leftItem, rightItem, expectedResult, null
+        );
+    }
+}

src/test/java/xyz/alexcrea/cuanvil/util/AnvilFuseTestUtil.java

@@ -0,0 +1,138 @@
+package xyz.alexcrea.cuanvil.util;
+
+import io.delilaheve.util.ItemUtil;
+import org.bukkit.Material;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.PrepareAnvilEvent;
+import org.bukkit.inventory.AnvilInventory;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import xyz.alexcrea.cuanvil.enchant.CAEnchantment;
+import xyz.alexcrea.cuanvil.listener.PrepareAnvilListener;
+import xyz.alexcrea.cuanvil.mock.AnvilViewMock;
+import xyz.alexcrea.cuanvil.mock.EnchantedItemStackMock;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+public class AnvilFuseTestUtil {
+
+    public static ItemStack prepareItem(@NotNull Material material,
+                                        @NotNull List<CAEnchantment> enchantments,
+                                        @NotNull List<Integer> level){
+        Assertions.assertEquals(enchantments.size(), level.size());
+
+        HashMap<CAEnchantment, Integer> enchantmentMap = new HashMap<>();
+        for (int i = 0; i < enchantments.size(); i++) {
+            enchantmentMap.put(enchantments.get(i), level.get(i));
+        }
+
+        ItemStack item = new EnchantedItemStackMock(material);
+        ItemUtil.INSTANCE.setEnchantmentsUnsafe(item, enchantmentMap);
+
+        return item;
+    }
+
+
+    public static ItemStack prepareItem(@NotNull Material material,
+                                        @NotNull List<String> enchantmentNames,
+                                        Integer... levels){
+        List<CAEnchantment> enchantments = new ArrayList<>();
+
+        for (String enchantmentName : enchantmentNames) {
+            List<CAEnchantment> enchantmentList = CAEnchantment.getListByName(enchantmentName);
+            Assertions.assertNotEquals(0, enchantmentList.size(),
+                    "Could not find enchantment \"" + enchantmentName + "\"");
+
+            enchantments.addAll(enchantmentList);
+        }
+
+        return prepareItem(material, enchantments, List.of(levels));
+    }
+
+
+    /*
+     * Need to use that as it seems setting item in the inventory will not trigger the anvil click even
+     *
+     * Not the best for non-custom anvil plugins but work in the context of CA
+     */
+    public static void imitateAnvilUpdate(
+            @NotNull HumanEntity player,
+            @NotNull AnvilInventory anvil) {
+
+        AnvilViewMock view = new AnvilViewMock(player, anvil);
+        try {
+            PrepareAnvilEvent event = new PrepareAnvilEvent(view, anvil.getItem(2));
+
+            // Not ideal but possible and the easiest so why not
+            new PrepareAnvilListener().anvilCombineCheck(event);
+            anvil.setResult(event.getResult());
+        } catch (Exception e){
+            e.printStackTrace();
+            Assertions.fail();
+        }
+    }
+
+    public static void executeAnvilTest(
+            @NotNull AnvilInventory anvil,
+            @NotNull HumanEntity player,
+            @NotNull AnvilFuseTestData data
+            ){
+        Assertions.assertEquals(player.getOpenInventory().getTopInventory(), anvil,
+                "Openned inventory is not anvil");
+
+        // Test with only the left item
+        testPlacingItem(anvil, player,
+                0, data.expectedPriceAfterLeftPlaced(),
+                data.leftItem(), data.expectedAfterLeftPlaced());
+
+        // Test with only the right item
+        anvil.setItem(0, null); // We only want the right item. so we remove the left one
+        testPlacingItem(anvil, player,
+                1, data.expectedPriceAfterRightPlaced(),
+                data.rightItem(), data.expectedAfterRightPlaced());
+
+        // Test with both placed
+        testPlacingItem(anvil, player,
+                0, data.expectedPriceAfterBothPlaced(),
+                data.leftItem(), data.expectedResult());
+
+        // Sadly, can't currently test player click
+
+    }
+
+    @SuppressWarnings({"removal"})
+    private static void testPlacingItem(
+            @NotNull AnvilInventory anvil,
+            @NotNull HumanEntity player,
+            int slot,
+            Integer expectedPrice,
+            @Nullable ItemStack toPlace,
+            @Nullable ItemStack expectedResult){
+        anvil.setItem(slot, toPlace);
+        AnvilFuseTestUtil.imitateAnvilUpdate(player, anvil);
+
+        ItemStack result = anvil.getItem(2);
+        assertEqual(result, expectedResult);
+        assertPriceEqual(expectedPrice, anvil.getRepairCost());
+    }
+
+    public static void assertEqual(@Nullable ItemStack item1, @Nullable ItemStack item2) {
+        if(isAir(item1)) Assertions.assertTrue(isAir(item2));
+        else Assertions.assertEquals(item1, item2);
+
+    }
+
+    public static boolean isAir(@Nullable ItemStack item){
+        return item == null || item.isEmpty();
+    }
+
+    public static void assertPriceEqual(Integer expectedPrice, int price){
+        if(expectedPrice == null) return;
+        Assertions.assertEquals(price, expectedPrice);
+    }
+
+}

src/test/java/xyz/alexcrea/cuanvil/util/CommonItemUtil.java

@@ -0,0 +1,21 @@
+package xyz.alexcrea.cuanvil.util;
+
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+
+import java.util.List;
+
+public class CommonItemUtil {
+
+    public static ItemStack sharpness(int level){
+        return AnvilFuseTestUtil.prepareItem(
+                Material.DIAMOND_SWORD,
+                List.of("sharpness"),
+                level
+        );
+    }
+
+
+
+
+}