src/main/java/Inventory/Inventory.java

@@ -1,27 +1,33 @@
 package Inventory;
 
 import Item.Item;
+import Item.ItemStack;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
 public class Inventory {
-    List<Item> items;
+    List<ItemStack> items;
 
     public Inventory() {
         items = new ArrayList<>();
     }
 
-    public List<Item> getItems() {
+    public List<ItemStack> getItems() {
         return Collections.unmodifiableList(items);
     }
 
-    public void addItem(Item item) {
+    public void addItem(ItemStack item) {
         items.add(item);
     }
 
-    public boolean containsItem(String item) {
+    public boolean containsItem(Item item) {
-        return items.contains(item);
+        for (ItemStack stack : items) {
+            if (stack.item().equals(item)) {
+                return true;
+            }
+        }
+        return false;
     }
 }

src/main/java/Item/ItemStack.java

@@ -0,0 +1,16 @@
+package Item;
+
+public record ItemStack(Item item, int quantity) {
+    public ItemStack {
+        if (quantity <= 0) {
+            throw new IllegalArgumentException("Quantity must be greater than zero.");
+        }
+    }
+    public Item getItem() {
+        return item;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+}

src/main/java/Job/Miner.java

@@ -1,6 +1,7 @@
 package Job;
 
 import Inventory.HasInventory;
+import Item.ItemStack;
 import Terrain.Biome;
 
 
@@ -18,6 +19,6 @@ public class Miner extends Job {
 
     public void dig(Biome biome) {
         var item = biome.getLootTable().roll();
-        actor.getInventory().addItem(item);
+        actor.getInventory().addItem(new ItemStack(item, 1));
     }
 }

src/test/java/InventoryTest.java

@@ -1,5 +1,6 @@
 import Inventory.Inventory;
 import Item.BasicItem;
+import Item.ItemStack;
 import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -9,9 +10,27 @@ public class InventoryTest {
     @Test
     void can_add_item_to_inventory() {
         var inventory = new Inventory();
-        inventory.addItem(new BasicItem("iron_sword", "Iron Sword"));
+        var item = new BasicItem("iron_sword", "Iron Sword");
+        inventory.addItem(new ItemStack(item, 1));
         assertThat(inventory.getItems(), hasItem(
+                hasProperty("item",
                         hasProperty("id", equalTo("iron_sword"))
+                )
+        ));
+        }
+
+        @Test
+    void can_add_quantity_to_inventory() {
+        var inventory = new Inventory();
+        var item = new BasicItem("iron_sword", "Iron Sword");
+        var stack = new ItemStack(item, 5);
+        inventory.addItem(stack);
+        assertThat(inventory.getItems(), hasItem(
+                allOf(
+                        hasProperty("item",
+                                hasProperty("id", equalTo("iron_sword"))),
+                        hasProperty("quantity", equalTo(5))
+                )
         ));
     }
 }

src/test/java/MinerTest.java

@@ -46,7 +46,7 @@ public class MinerTest {
         Biome.COAST.getLootTable().setRandomProvider(random);
         job.dig(Biome.COAST);
         assertThat(job.getActor().getInventory().getItems(), hasItem(
-                hasProperty("id", equalTo("sand"))));
+                hasProperty("item", hasProperty("id", equalTo("sand")))));
     }
 
     @Test
@@ -55,7 +55,11 @@ public class MinerTest {
         var job = new Miner(defaultPlayer());
         Biome.MOUNTAIN.getLootTable().setRandomProvider(random);
         job.dig(Biome.MOUNTAIN);
-        assertThat(job.getActor().getInventory().getItems(), hasItem( hasProperty("id", equalTo("iron"))));
+            assertThat(job.getActor().getInventory().getItems(), hasItem(
+                    hasProperty("item",
+                            hasProperty("id", equalTo("iron")))
+                    )
+            );
     }
 }