Added code smell for npc/CustomerManager file

source/core/src/test/com/csse3200/game/components/npc/CustomerManagerTest.java

@@ -0,0 +1,71 @@
+package com.csse3200.game.components.npc;
+
+import com.csse3200.game.entities.Entity;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.logging.Logger;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class CustomerManagerTest {
+
+    private Entity testCustomer;
+    private String testOrderNumber = "12345";
+    private static final Logger logger = Logger.getLogger(CustomerManager.class.getName());
+
+    @BeforeEach
+    public void setUp() {
+        // Initialize a test customer entity
+        testCustomer = new Entity();
+        // Reset the CustomerManager map before each test
+        CustomerManager.reset();
+    }
+
+    @Test
+    public void testAddCustomer() {
+        // Add a customer to the manager
+        CustomerManager.addCustomer(testOrderNumber, testCustomer);
+        // Verify the customer was added
+        assertEquals(testCustomer, CustomerManager.getCustomerByOrder(testOrderNumber), 
+                     "The customer should be added to the map");
+    }
+
+    @Test
+    public void testGetCustomerByOrder() {
+        // Add a customer and retrieve it
+        CustomerManager.addCustomer(testOrderNumber, testCustomer);
+        Entity retrievedCustomer = CustomerManager.getCustomerByOrder(testOrderNumber);
+        // Verify that the retrieved customer matches the added one
+        assertEquals(testCustomer, retrievedCustomer, 
+                     "The retrieved customer should match the one that was added");
+    }
+
+    @Test
+    public void testRemoveCustomerByOrder() {
+        // Add a customer and then remove it
+        CustomerManager.addCustomer(testOrderNumber, testCustomer);
+        CustomerManager.removeCustomerByOrder(testOrderNumber);
+        // Verify the customer is no longer in the map
+        assertNull(CustomerManager.getCustomerByOrder(testOrderNumber), 
+                   "The customer should be removed from the map");
+    }
+
+    @Test
+    public void testReset() {
+        // Add a customer, then reset the map
+        CustomerManager.addCustomer(testOrderNumber, testCustomer);
+        CustomerManager.reset();
+        // Verify the map is empty
+        assertNull(CustomerManager.getCustomerByOrder(testOrderNumber), 
+                   "The map should be empty after reset");
+    }
+
+    @Test
+    public void testPrintMessage() {
+        // Add a customer and verify that printMessage() runs without errors
+        CustomerManager.addCustomer(testOrderNumber, testCustomer);
+        assertDoesNotThrow(() -> CustomerManager.printMessage(), 
+                           "printMessage() should not throw an exception");
+    }
+}