test(Product): 상품 구매 동시성 제어 테스트 추가

src/test/java/com/sportsecho/product/ProductTest.java

@@ -15,10 +15,4 @@ public interface ProductTest {
         .price(TEST_PRICE)
         .quantity(TEST_QUANTITY)
         .build();
-    Product ANOTHER_TEST_PRODUCT = Product.builder()
-        .title(TEST_PRODUCT_TITLE)
-        .content(TEST_PRODUCT_CONTENT)
-        .price(TEST_PRICE)
-        .quantity(TEST_QUANTITY)
-        .build();
 }

src/test/java/com/sportsecho/purchase/service/PurchaseServiceImplV1Test.java

@@ -1,14 +1,18 @@
 package com.sportsecho.purchase.service;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.sportsecho.common.exception.GlobalException;
+import com.sportsecho.hotdeal.service.PurchaseHotdealTest;
 import com.sportsecho.member.MemberTest;
 import com.sportsecho.member.MemberTestUtil;
 import com.sportsecho.member.entity.Member;
+import com.sportsecho.member.entity.MemberRole;
 import com.sportsecho.member.repository.MemberRepository;
+import com.sportsecho.memberProduct.MemberProductTest;
 import com.sportsecho.memberProduct.MemberProductTestUtil;
 import com.sportsecho.memberProduct.entity.MemberProduct;
 import com.sportsecho.memberProduct.repository.MemberProductRepository;
@@ -23,15 +27,23 @@
 import com.sportsecho.purchase.exception.PurchaseErrorCode;
 import com.sportsecho.purchase.repository.PurchaseRepository;
 import com.sportsecho.purchaseProduct.repository.PurchaseProductRepository;
+import jakarta.persistence.EntityManager;
+import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
 import org.springframework.test.context.ActiveProfiles;
+import org.springframework.transaction.annotation.Transactional;
 
 @ActiveProfiles("test")
 @SpringBootTest
@@ -55,6 +67,9 @@ class PurchaseServiceImplV1Test implements MemberTest, ProductTest, PurchaseTest
     @Autowired
     PurchaseServiceImplV1 purchaseService;
 
+    @Autowired
+    EntityManager em;
+
     Member member;
     Product product;
     MemberProduct memberProduct;
@@ -102,6 +117,79 @@ void purchaseTest_success() {
                 productRepository.findAll().get(0).getQuantity());
         }
 
+        /**
+         * 사용자가 자신의 장바구니에 있는 상품의 구매 버튼을 눌렀을때 발생하는 동시성 이슈에 대한 테스트
+         * 상품 구매 중 상품 version이 바뀌었다면 동시성 처리를 위해 ObjectOptimisticLockingFailureException 발생
+         * 낙관적락을 이용해 동시성 제어가 잘 이루어지는지 확인하고 데이터 정합성 검증
+         * */
+        @Test
+        @DisplayName("구매 실패 - 동일 상품에 다수의 구매 요청이 들어오는 경우")
+        void purchaseTest_fail_concurrency() throws InterruptedException {
+            //given
+            int numberOfThreads = 10;
+            int beforeQuantity = product.getQuantity();
+
+            /* 테스트용 member 생성 */
+            Member[] members = new Member[numberOfThreads];
+            for (int i = 0; i < numberOfThreads; i++) {
+                members[i] = memberRepository.save(
+                    MemberTestUtil.getTestMember(
+                        TEST_MEMBER_NAME,
+                        TEST_PASSWORD,
+                        TEST_EMAIL + i,
+                        MemberRole.CUSTOMER
+                    )
+                );
+            }
+
+            /* 테스트용 장바구니 생성 및 저장 */
+            for (int i = 0; i < numberOfThreads; i++) {
+                memberProductRepository.save(
+                    MemberProductTestUtil.getMemberProduct(members[i], product)
+                );
+            }
+
+            /* exception count를 위한 boolean flag */
+            boolean[] exceptionFlag = new boolean[members.length];
+
+            ExecutorService service = Executors.newFixedThreadPool(numberOfThreads);
+            CountDownLatch latch = new CountDownLatch(numberOfThreads);
+
+            //when
+            for (int i = 0; i < numberOfThreads; i++) {
+                final int idx = i;
+                service.execute(() -> {
+                    try {
+                        purchaseService.purchase(requestDto, members[idx]);
+                    /* OptimisticLock과 재고부족으로 발생하는 예외처리 */
+                    } catch(ObjectOptimisticLockingFailureException | GlobalException e) {
+                        exceptionFlag[idx] = true;
+                    } finally {
+                        latch.countDown();
+                    }
+                });
+            }
+
+            latch.await();
+            service.shutdown();
+
+            int exceptionCount = 0;
+            for (boolean flag : exceptionFlag) {
+                if(flag) exceptionCount++;
+            }
+
+            //then
+            /* 테스트클래스의 product와 서비스 로직의 memberProduct.getProduct()는 quantity의 더티체킹이 진행되지 않음 */
+            Product findProduct = productRepository.findById(product.getId()).orElse(null);
+            assertNotNull(findProduct);
+
+            /* 데이터 정합성 검증 */
+            int expectQuantity = beforeQuantity -
+                (numberOfThreads-exceptionCount)*MemberProductTest.TEST_QUANTITY;
+            int actualQuantity = findProduct.getQuantity();
+            assertEquals(expectQuantity, actualQuantity);
+        }
+
         @Test
         @DisplayName("구매 실패 - 장바구니가 비어있음")
         void purchaseTest_fail_emptyCart() {