Add tests for CashShopSurpriseHandler

src/test/java/testutil/Items.java

@@ -0,0 +1,10 @@
+package testutil;
+
+import client.inventory.Item;
+
+public class Items {
+
+    public static Item itemWithQuantity(int itemId, int quantity) {
+        return new Item(itemId, AnyValues.anyShort(), (short) quantity);
+    }
+}