Fix #1152: EU is left in a hidden buffer when Diesel Generator runs out of fuel

src/main/java/aztech/modern_industrialization/machines/components/FluidItemConsumerComponent.java

@@ -117,6 +117,10 @@ public long getEuProduction(List<ConfigurableFluidStack> fluidInputs,
 
         long euProduced = 0;
 
+        // Consume from the buffer first
+        euProduced += euBuffer;
+        euBuffer = 0;
+
         for (ConfigurableFluidStack stack : fluidInputs) {
             Fluid fluid = stack.getResource().getFluid();
             if (fluidEUProductionMap.accept(fluid) && stack.getAmount() > 0) {

src/main/java/aztech/modern_industrialization/test/GeneratorTests.java

@@ -0,0 +1,63 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Azercoco & Technici4n
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package aztech.modern_industrialization.test;
+
+import aztech.modern_industrialization.MI;
+import aztech.modern_industrialization.MIFluids;
+import aztech.modern_industrialization.machines.blockentities.GeneratorMachineBlockEntity;
+import aztech.modern_industrialization.test.framework.MIGameTest;
+import aztech.modern_industrialization.test.framework.MIGameTestHelper;
+import aztech.modern_industrialization.thirdparty.fabrictransfer.api.transaction.Transaction;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.core.registries.BuiltInRegistries;
+
+public class GeneratorTests {
+    /**
+     * Regression test for <a href="https://github.com/AztechMC/Modern-Industrialization/issues/1152">issue 1152</a>:
+     * "EU is left in a hidden buffer when Diesel Generator runs out of fuel".
+     */
+    @MIGameTest
+    public void testGeneratorEmptiesEuBuffer(MIGameTestHelper helper) {
+        var generatorPos = new BlockPos(0, 1, 0);
+        var lvDieselGeneratorBlock = BuiltInRegistries.BLOCK.getOptional(MI.id("lv_diesel_generator")).orElseThrow();
+        helper.setBlock(generatorPos, lvDieselGeneratorBlock);
+
+        var dieselGenerator = (GeneratorMachineBlockEntity) helper.getBlockEntity(generatorPos);
+
+        try (var tx = Transaction.openOuter()) {
+            long inserted = dieselGenerator.getInventory().fluidStorage.insert(MIFluids.BIODIESEL.variant(), 1, tx);
+            helper.assertValueEqual(inserted, 1L, "inserted biodiesel");
+            tx.commit();
+        }
+
+        // Should produce 64 per tick: 192 after 3 ticks and only 250 (the biodiesel value) after 4 ticks
+        helper.startSequence()
+                .thenIdle(3)
+                .thenExecute(() -> helper.assertEnergy(generatorPos, 192, Direction.NORTH))
+                .thenIdle(1)
+                .thenExecute(() -> helper.assertEnergy(generatorPos, 250, Direction.NORTH))
+                .thenSucceed();
+    }
+}

src/main/java/aztech/modern_industrialization/test/framework/MIGameTestHelper.java

@@ -24,6 +24,7 @@
 package aztech.modern_industrialization.test.framework;
 
 import aztech.modern_industrialization.MIBlock;
+import aztech.modern_industrialization.api.energy.EnergyApi;
 import aztech.modern_industrialization.blocks.storage.tank.creativetank.CreativeTankBlockEntity;
 import aztech.modern_industrialization.materials.MIMaterials;
 import aztech.modern_industrialization.materials.Material;
@@ -35,12 +36,14 @@
 import aztech.modern_industrialization.thirdparty.fabrictransfer.api.fluid.FluidVariant;
 import java.util.function.Consumer;
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
 import net.minecraft.core.registries.BuiltInRegistries;
 import net.minecraft.gametest.framework.GameTestHelper;
 import net.minecraft.gametest.framework.GameTestInfo;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.material.Fluid;
 import net.neoforged.neoforge.capabilities.Capabilities;
+import org.jetbrains.annotations.Nullable;
 
 public class MIGameTestHelper extends GameTestHelper {
     public MIGameTestHelper(GameTestInfo testInfo) {
@@ -122,4 +125,15 @@ public void assertNoFluid(BlockPos pos) {
             }
         }
     }
+
+    public void assertEnergy(BlockPos pos, long energy, @Nullable Direction side) {
+        var miEnergyHandler = getLevel().getCapability(EnergyApi.SIDED, absolutePos(pos), side);
+        if (miEnergyHandler == null) {
+            fail("Could not find energy handler", pos);
+        }
+        long storedEnergy = miEnergyHandler.getAmount();
+        if (storedEnergy != energy) {
+            fail("Expected energy to be " + energy + ", was " + storedEnergy, pos);
+        }
+    }
 }

src/main/java/aztech/modern_industrialization/test/framework/MIGameTests.java

@@ -25,6 +25,7 @@
 
 import aztech.modern_industrialization.MI;
 import aztech.modern_industrialization.test.FluidPipeTests;
+import aztech.modern_industrialization.test.GeneratorTests;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
@@ -37,7 +38,8 @@ private MIGameTests() {
     }
 
     private static final List<Class<?>> TEST_CLASSES = List.of(
-            FluidPipeTests.class);
+            FluidPipeTests.class,
+            GeneratorTests.class);
 
     @GameTestGenerator
     public static List<TestFunction> generateTests() {