src/main/java/Shared/LootTable.java

@@ -0,0 +1,24 @@
+package Shared;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Random;
+
+public class LootTable<T> {
+    private Random random = new Random();
+    private final List<T> items =  new ArrayList<>();
+
+    public LootTable(Random random) {
+        this.random = random;
+    }
+
+    public void addEntry(T entry, int weight) {
+        items.add(entry);
+    }
+
+    public T roll() {
+       return items.getFirst();
+    }
+
+}

src/test/java/LootTableTest.java

@@ -0,0 +1,37 @@
+import Shared.LootTable;
+import org.junit.jupiter.api.Test;
+
+import java.util.Random;
+
+import static org.hamcrest.CoreMatchers.anyOf;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class LootTableTest {
+    LootTable<String> defaultLootTable() {
+        LootTable<String> lootTable = new LootTable<>();
+        lootTable.addEntry("Stone", 90);
+        lootTable.addEntry("Iron", 10);
+        return lootTable;
+    }
+
+    @Test
+    void returns_an_item_was_added() {
+       LootTable<String> loot = defaultLootTable();
+       String result = loot.roll();
+       assertThat(result, anyOf(equalTo("Stone"), equalTo("Iron")));
+    }
+
+    void respects_weight_when_rolling() {
+        var mockRandom = mock(Random.class);
+        when(mockRandom.nextInt(anyInt())).thenReturn(94);
+        LootTable<String> loot = new LootTable<>(mockRandom);
+        loot.addEntry("Stone", 90);
+        loot.addEntry("Iron", 10);
+        String result = loot.roll();
+        assertThat(result, equalTo("Iron"));
+    }
+}