Adding basic unit test for IDropCalculationStrategy

src/main/java/com/l2jserver/gameserver/model/drops/strategy/IDropCalculationStrategy.java

@@ -18,7 +18,6 @@
  */
 package com.l2jserver.gameserver.model.drops.strategy;
 
-import java.util.Collections;
 import java.util.List;
 
 import com.l2jserver.commons.util.Rnd;
@@ -41,7 +40,7 @@ public interface IDropCalculationStrategy {
 				}
 			}
 			
-			return Collections.singletonList(new ItemHolder(item.getItemId(), Rnd.get(item.getMin(victim), item.getMax(victim)) * amountMultiply));
+			return List.of(new ItemHolder(item.getItemId(), Rnd.get(item.getMin(victim), item.getMax(victim)) * amountMultiply));
 		}
 		
 		return null;

src/test/java/com/l2jserver/gameserver/model/drops/strategy/IDropCalculationStrategyTest.java

@@ -0,0 +1,49 @@
+package com.l2jserver.gameserver.model.drops.strategy;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.mockStatic;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import com.l2jserver.commons.util.Rnd;
+import com.l2jserver.gameserver.model.actor.L2Character;
+import com.l2jserver.gameserver.model.drops.GeneralDropItem;
+
+/**
+ * IDropCalculationStrategy test.
+ * @author Zoey76
+ * @version 2.6.3.0
+ */
+@ExtendWith(MockitoExtension.class)
+class IDropCalculationStrategyTest {
+	
+	private static final int ITEM_ID = 51424;
+	
+	@Mock
+	private GeneralDropItem item;
+	
+	@Mock
+	private L2Character victim;
+	
+	@Mock
+	private L2Character killer;
+	
+	@Test
+	void testDefaultStrategy() {
+		when(item.getItemId()).thenReturn(ITEM_ID);
+		when(item.getChance(victim, killer)).thenReturn(150d);
+		when(item.isPreciseCalculated()).thenReturn(true);
+		try (var rnd = mockStatic(Rnd.class)) {
+			rnd.when(Rnd::nextDouble).thenReturn(0.1d);
+			rnd.when(() -> Rnd.get(anyLong(), anyLong())).thenReturn(1L);
+			final var drops = IDropCalculationStrategy.DEFAULT_STRATEGY.calculateDrops(item, victim, killer);
+			assertEquals(ITEM_ID, drops.get(0).getId());
+			assertEquals(2, drops.get(0).getCount());
+		}
+	}
+}