Fix Dark Tank loot function: set capacity before inserting fluid, add game tests

Agent-Logs-Url: https://github.com/CyclopsMC/EvilCraft/sessions/b8e2ebee-6bde-4d7e-9591-545b7042754d

Co-authored-by: rubensworks <440384+rubensworks@users.noreply.github.com>

Author: Copilot

src/main/java/org/cyclops/evilcraft/EvilCraft.java

@@ -470,6 +470,7 @@ public Class<?>[] getGameTestClasses() {
                 GameTestsBlockEternalWater.class,
                 GameTestsBloodChest.class,
                 GameTestsBloodInfuser.class,
+                GameTestsDarkTank.class,
                 GameTestsEntangledChalice.class,
                 GameTestsItemEternalWater.class,
                 GameTestsItemStacking.class,

src/main/java/org/cyclops/evilcraft/gametest/GameTestsDarkTank.java

@@ -0,0 +1,83 @@
+package org.cyclops.evilcraft.gametest;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.network.chat.Component;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.item.ItemStack;
+import net.neoforged.neoforge.capabilities.Capabilities;
+import net.neoforged.neoforge.fluids.FluidStack;
+import net.neoforged.neoforge.transfer.ResourceHandler;
+import net.neoforged.neoforge.transfer.access.ItemAccess;
+import net.neoforged.neoforge.transfer.fluid.FluidResource;
+import org.cyclops.cyclopscore.gametest.GameTest;
+import org.cyclops.evilcraft.Reference;
+import org.cyclops.evilcraft.RegistryEntries;
+import org.cyclops.evilcraft.blockentity.BlockEntityDarkTank;
+
+public class GameTestsDarkTank {
+
+    public static final String TEMPLATE_EMPTY = Reference.MOD_ID + ":empty10";
+    public static final BlockPos POS = BlockPos.ZERO.offset(2, 1, 2);
+
+    /**
+     * Tests that breaking a large Dark Tank (144,000mB capacity) drops an item that preserves
+     * the full capacity and fluid amount, not just the base 16,000mB capacity.
+     */
+    @GameTest(template = TEMPLATE_EMPTY)
+    public void testBreakLargeDarkTankFullPreservesCapacityAndFluid(GameTestHelper helper) {
+        int largeCapacity = BlockEntityDarkTank.BASE_CAPACITY * 9;
+
+        // Place a Dark Tank
+        helper.setBlock(POS, RegistryEntries.BLOCK_DARK_TANK.get());
+        BlockEntityDarkTank tank = helper.getBlockEntity(POS, BlockEntityDarkTank.class);
+
+        // Set up as a large tank filled with blood
+        tank.getTank().setCapacity(largeCapacity);
+        tank.getTank().setFluid(new FluidStack(RegistryEntries.FLUID_BLOOD, largeCapacity));
+
+        // Break the block to trigger the loot table (which calls LootFunctionCopyTankData)
+        helper.destroyBlock(POS);
+
+        helper.succeedWhen(() -> {
+            ItemStack result = helper.findOneEntity(EntityType.ITEM).getItem();
+            helper.assertValueEqual(result.getItem(), RegistryEntries.ITEM_DARK_TANK.get(), Component.literal("Dropped item should be a Dark Tank"));
+
+            ItemAccess itemAccess = ItemAccess.forStack(result);
+            ResourceHandler<FluidResource> fluidHandler = result.getCapability(Capabilities.Fluid.ITEM, itemAccess);
+            helper.assertTrue(fluidHandler != null, Component.literal("Dropped Dark Tank should have a fluid handler"));
+            helper.assertValueEqual(fluidHandler.getCapacityAsInt(0, FluidResource.EMPTY), largeCapacity, Component.literal("Dropped Dark Tank should have large capacity"));
+            helper.assertValueEqual(fluidHandler.getAmountAsInt(0), largeCapacity, Component.literal("Dropped Dark Tank should contain all fluid"));
+        });
+    }
+
+    /**
+     * Tests that breaking an empty large Dark Tank preserves the large capacity.
+     */
+    @GameTest(template = TEMPLATE_EMPTY)
+    public void testBreakEmptyLargeDarkTankPreservesCapacity(GameTestHelper helper) {
+        int largeCapacity = BlockEntityDarkTank.BASE_CAPACITY * 9;
+
+        // Place a Dark Tank
+        helper.setBlock(POS, RegistryEntries.BLOCK_DARK_TANK.get());
+        BlockEntityDarkTank tank = helper.getBlockEntity(POS, BlockEntityDarkTank.class);
+
+        // Set up as a large tank with no fluid
+        tank.getTank().setCapacity(largeCapacity);
+
+        // Break the block
+        helper.destroyBlock(POS);
+
+        helper.succeedWhen(() -> {
+            ItemStack result = helper.findOneEntity(EntityType.ITEM).getItem();
+            helper.assertValueEqual(result.getItem(), RegistryEntries.ITEM_DARK_TANK.get(), Component.literal("Dropped item should be a Dark Tank"));
+
+            ItemAccess itemAccess = ItemAccess.forStack(result);
+            ResourceHandler<FluidResource> fluidHandler = result.getCapability(Capabilities.Fluid.ITEM, itemAccess);
+            helper.assertTrue(fluidHandler != null, Component.literal("Dropped Dark Tank should have a fluid handler"));
+            helper.assertValueEqual(fluidHandler.getCapacityAsInt(0, FluidResource.EMPTY), largeCapacity, Component.literal("Empty dropped Dark Tank should preserve large capacity"));
+            helper.assertValueEqual(fluidHandler.getAmountAsInt(0), 0, Component.literal("Dropped Dark Tank should be empty"));
+        });
+    }
+
+}

src/main/java/org/cyclops/evilcraft/loot/functions/LootFunctionCopyTankData.java

@@ -39,14 +39,14 @@ public ItemStack run(ItemStack itemStack, LootContext lootContext) {
             return Optional.ofNullable(itemAccess.getCapability(Capabilities.Fluid.ITEM))
                     .map(fluidHandlerItem -> {
                         try (var tx = Transaction.openRoot()) {
+                            if (fluidHandlerItem instanceof IFluidHandlerCapacity) {
+                                ((IFluidHandlerCapacity) fluidHandlerItem).setTankCapacity(0, fluidHandlerTile.getTankCapacity(0), tx);
+                            }
                             FluidResource resource = fluidHandlerTile.getResource(0);
                             if (!resource.isEmpty()) {
                                 fluidHandlerItem.insert(resource, fluidHandlerTile.getFluidAmount(), tx);
-                                if (fluidHandlerItem instanceof IFluidHandlerCapacity) {
-                                    ((IFluidHandlerCapacity) fluidHandlerItem).setTankCapacity(0, fluidHandlerTile.getTankCapacity(0), tx);
-                                }
-                                tx.commit();
                             }
+                            tx.commit();
                         }
                         return itemAccess.getResource().toStack(itemAccess.getAmount());
                     }).orElse(itemStack);