[Order API test: ProductService addProduct test

product-order-service/src/test/java/com/example/productorderservice/product/ProductServiceTest.java

@@ -0,0 +1,116 @@
+package com.example.productorderservice.product;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.util.Assert;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ProductServiceTest {
+
+    private ProductService productService;
+    private ProductPort productPort;
+    private ProductRepository productRepository;
+
+    @BeforeEach
+    void setUp() {
+        productRepository = new ProductRepository();
+        productPort = new ProductAdapter(productRepository);
+        productService = new ProductService(productPort);
+    }
+
+    @Test
+    void 상품등록() {
+        final String name = "상품명";
+        final int price = 1000;
+        final DiscountPolicy discountPolicy = DiscountPolicy.NONE;
+        final AddProductRequest request = new AddProductRequest(name, price, discountPolicy); // 02. Request 클래스 생성
+
+        productService.addProduct(request); // 01. 상품 등록 서비스 호출
+    }
+
+    /**
+     * 03. Request 는 record 로 사용 가능
+     */
+    private record AddProductRequest(String name, int price, DiscountPolicy discountPolicy) {
+        private AddProductRequest {
+            // 03-1. Assert 를 활용해서 파라미터 체크
+            Assert.hasText(name, "상품명은 필수입니다.");
+            Assert.isTrue(price > 0, "상품 가격은 0보다 커야 합니다.");
+            Assert.notNull(discountPolicy, "할인 정책은 필수입니다.");
+        }
+    }
+
+    private enum DiscountPolicy {
+        NONE
+    }
+
+    /**
+     * 04. ProductService 메서드 구현
+     */
+    private class ProductService {
+        private final ProductPort productPort;
+
+        private ProductService(final ProductPort productPort) {
+            this.productPort = productPort;
+        }
+
+        public void addProduct(final AddProductRequest request) {
+            final Product product = new Product(request.name(), request.price(), request.discountPolicy()); // 05. Product 클래스 생성
+
+            productPort.save(product);
+        }
+    }
+
+    private class Product {
+        private Long id;
+        private final String name;
+        private final int price;
+        private final DiscountPolicy discountPolicy;
+
+        public Product(final String name, final int price, final DiscountPolicy discountPolicy) {
+            Assert.hasText(name, "상품명은 필수입니다.");
+            Assert.isTrue(price > 0, "상품 가격은 0보다 커야 합니다.");
+            Assert.notNull(discountPolicy, "할인 정책은 필수입니다.");
+            this.name = name;
+            this.price = price;
+            this.discountPolicy = discountPolicy;
+        }
+
+        public void assigId(final Long id) {
+            this.id = id;
+        }
+
+        public Long getId() {
+            return id;
+        }
+    }
+
+    private interface ProductPort {
+        void save(final Product product);
+    }
+
+    private class ProductAdapter implements ProductPort {
+        private final ProductRepository productRepository;
+
+        private ProductAdapter(final ProductRepository productRepository) {
+            this.productRepository = productRepository;
+        }
+
+        @Override
+        public void save(final Product product) {
+            productRepository.save(product);
+        }
+    }
+
+    private class ProductRepository {
+        private Map<Long, Product> persistence = new HashMap<>();
+        private Long sequence = 0L;
+
+        public void save(final Product product) {
+            product.assigId(++sequence);
+            persistence.put(product.getId(), product);
+        }
+    }
+}