Add test for GameManager loading mek onto dropship

megamek/unittests/megamek/common/DropShipMekLoadTest.java

@@ -0,0 +1,60 @@
+package megamek.common;
+
+import megamek.common.enums.GamePhase;
+import megamek.common.net.enums.PacketCommand;
+import megamek.common.net.packets.Packet;
+import megamek.common.verifier.TestEntity;
+import megamek.server.GameManager;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+public class DropShipMekLoadTest {
+
+    @Test
+    public void test() throws Exception {
+        MechSummaryCache instance = MechSummaryCache.getInstance(true);
+        Mech atlas = (Mech) instance.getMech("Atlas AS7-D").loadEntity();
+        atlas.setId(2);
+        Dropship leopard = (Dropship) instance.getMech("Leopard (2537)").loadEntity();
+        leopard.setId(1);
+
+        Game game = new Game();
+        game.setPhase(GamePhase.LOUNGE);
+        game.addPlayer(0, new Player(0, "TestPlayer"));
+        game.addEntity(atlas);
+        game.addEntity(leopard);
+
+        GameManager gm = mock(GameManager.class);
+        doNothing().when(gm).entityUpdate(anyInt());
+        when(gm.getGame()).thenReturn(game);
+        doCallRealMethod().when(gm).setGame(any(Game.class));
+        doCallRealMethod().when(gm).handlePacket(anyInt(), any(Packet.class));
+        gm.setGame(game);
+
+        Packet packet = new Packet(PacketCommand.ENTITY_LOAD, atlas.getId(), leopard.getId(), -1);
+        gm.handlePacket(0, packet);
+
+        doAssertions(leopard, atlas);
+
+        leopard.setAltitude(0);
+
+        doAssertions(leopard, atlas);
+    }
+
+    private void doAssertions(Entity leopard, Entity atlas) {
+        StringBuffer errors = new StringBuffer();
+        assertTrue(isValid(leopard, errors), "Leopard is not valid after loading Atlas, errors: " + errors);
+        assertTrue(isValid(atlas, errors), "Atlas is not valid after loading onto Leopard, errors: " + errors);
+        assertEquals(atlas.getTransportId(), leopard.getId(),
+                "Carrier ID " + atlas.getTransportId() + " wrong, should be " + leopard.getId());
+        assertEquals(1, leopard.getLoadedUnits().size(),
+                "Loaded unit list size" + leopard.getLoadedUnits().size() + " wrong, should be 1");
+        assertNull(atlas.getPosition(), "Loaded Atlas position is " + atlas.getPosition() + ", should be null");
+    }
+
+    private boolean isValid(Entity entity, StringBuffer errors) {
+        return TestEntity.getEntityVerifier(entity).correctEntity(errors);
+    }
+}