Merge pull request #8762 from capellancitizen/fix-botforce-generator

Fixed BotForceRandomizer throwing/generating nothing when weight class not set

Author: HammerGS

MekHQ/src/mekhq/campaign/mission/BotForceRandomizer.java

@@ -302,7 +302,7 @@ public List<Entity> generateForce(List<Unit> playerUnits, List<Entity> botFixedE
         // distribution is centered on the focal weight class and has some chance of
         // going higher
         // or lower. The scale parameter of 0.4 produces a reasonable variance.
-        GammaDistribution gamma = new GammaDistribution(focalWeightClass / 0.4, 0.4);
+        GammaDistribution gamma = new GammaDistribution(targetWeightClass / 0.4, 0.4);
 
         // we use a double while loop here so that we start the whole thing over if we
         // overshoot force size

MekHQ/unittests/mekhq/campaign/mission/BotForceRandomizerTest.java

@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2026 The MegaMek Team. All Rights Reserved.
+ *
+ * This file is part of MekHQ.
+ *
+ * MekHQ is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (GPL),
+ * version 3 or (at your option) any later version,
+ * as published by the Free Software Foundation.
+ *
+ * MekHQ is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * A copy of the GPL should have been included with this project;
+ * if not, see <https://www.gnu.org/licenses/>.
+ *
+ * NOTICE: The MegaMek organization is a non-profit group of volunteers
+ * creating free software for the BattleTech community.
+ *
+ * MechWarrior, BattleMech, `Mech and AeroTech are registered trademarks
+ * of The Topps Company, Inc. All Rights Reserved.
+ *
+ * Catalyst Game Labs and the Catalyst Game Labs logo are trademarks of
+ * InMediaRes Productions, LLC.
+ *
+ * MechWarrior Copyright Microsoft Corporation. MekHQ was created under
+ * Microsoft's "Game Content Usage Rules"
+ * <https://www.xbox.com/en-US/developers/rules> and it is not endorsed by or
+ * affiliated with Microsoft.
+ */
+package mekhq.campaign.mission;
+
+import megamek.common.Player;
+import megamek.common.equipment.EquipmentType;
+import megamek.common.loaders.MekSummary;
+import megamek.common.units.Entity;
+import megamek.common.units.UnitType;
+import mekhq.campaign.Campaign;
+import mekhq.campaign.campaignOptions.CampaignOptions;
+import mekhq.campaign.unit.Unit;
+import mekhq.campaign.universe.IUnitGenerator;
+import mekhq.campaign.universe.UnitGeneratorParameters;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
+import testUtilities.MHQTestUtilities;
+
+import java.io.File;
+import java.util.List;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class BotForceRandomizerTest {
+    private Campaign mockCampaign;
+
+    private void initializeTest() {
+        // Set up a test campaign with a unit generator that produces only Griffin Sparkys.
+        // There's definitely room for these tests to cover more, but this at least checks that it
+        // doesn't throw when used in the way that Story Arcs do.
+        EquipmentType.initializeTypes();
+
+        MekSummary mockGeneratedMekSummary = mock(MekSummary.class);
+        when(mockGeneratedMekSummary.getSourceFile()).thenReturn(new File(MHQTestUtilities.TEST_UNIT_DATA_DIR +
+                                                                                "Griffin GRF-1E Sparky.mtf"));
+        when(mockGeneratedMekSummary.getEntryName()).thenReturn(null);
+
+        IUnitGenerator mockUnitGenerator = mock(IUnitGenerator.class);
+        when(mockUnitGenerator.generate(any(UnitGeneratorParameters.class))).thenReturn(mockGeneratedMekSummary);
+
+        mockCampaign = mock(Campaign.class);
+        when(mockCampaign.getUnitGenerator()).thenReturn(mockUnitGenerator);
+        when(mockCampaign.getPlayer()).thenReturn(new Player(1, "player"));
+        when(mockCampaign.getCampaignOptions()).thenReturn(new CampaignOptions());
+    }
+
+    @Test
+    public void testBotForceRandomizerAdjustedWeight() {
+        initializeTest();
+
+        Unit mockPlayerUnit = mock(Unit.class);
+        Entity mockPlayerUnitEntity = mock(Entity.class);
+        when(mockPlayerUnit.getEntity()).thenReturn(mockPlayerUnitEntity);
+
+        when(mockPlayerUnitEntity.getWeight()).thenReturn(55.0);
+        when(mockPlayerUnitEntity.getUnitType()).thenReturn(UnitType.MEK);
+
+        List<Unit> playerUnits = List.of(mockPlayerUnit);
+        List<Entity> fixedEntities = List.of();
+
+        BotForceRandomizer randomizer = new BotForceRandomizer();
+        randomizer.setBalancingMethod(BotForceRandomizer.BalancingMethod.WEIGHT_ADJ);
+        randomizer.setForceMultiplier(2.0);
+
+        List<Entity> generated = randomizer.generateForce(playerUnits, fixedEntities, mockCampaign);
+
+        // There should be two units generated, as the player units score 55 adjusted tons, and a Griffin scores 55
+        // adjusted tons.
+        assertEquals(2, generated.size());
+    }
+
+    @Test
+    public void testBotForceRandomizerBV() {
+        initializeTest();
+
+        Unit mockPlayerUnit = mock(Unit.class);
+        Entity mockPlayerUnitEntity = mock(Entity.class);
+        when(mockPlayerUnit.getEntity()).thenReturn(mockPlayerUnitEntity);
+        when(mockPlayerUnitEntity.calculateBattleValue()).thenReturn(1449);
+
+        List<Unit> playerUnits = List.of(mockPlayerUnit);
+        List<Entity> fixedEntities = List.of();
+
+        BotForceRandomizer randomizer = new BotForceRandomizer();
+        randomizer.setBalancingMethod(BotForceRandomizer.BalancingMethod.BV);
+        randomizer.setForceMultiplier(2.0);
+
+        List<Entity> generated = randomizer.generateForce(playerUnits, fixedEntities, mockCampaign);
+
+        // There should be two units generated, as the player units score 1449BV, the same as the
+        // Sparky.
+        assertEquals(2, generated.size());
+    }
+}