feat: 상품 목록 조회 기능 구현 (#22)

* fix: SQL syntax 오류 수정

* feat: 상품 엔티티 생성

* feat: 상품 목록 조회 API 구현

* test: 상품 목록 조회 테스트

* style: return 전 줄바꿈 추가

src/main/java/com/moabam/api/application/ProductService.java

@@ -0,0 +1,27 @@
+package com.moabam.api.application;
+
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.moabam.api.domain.entity.Product;
+import com.moabam.api.domain.repository.ProductRepository;
+import com.moabam.api.dto.ProductMapper;
+import com.moabam.api.dto.ProductsResponse;
+
+import lombok.RequiredArgsConstructor;
+
+@Service
+@Transactional(readOnly = true)
+@RequiredArgsConstructor
+public class ProductService {
+
+	private final ProductRepository productRepository;
+
+	public ProductsResponse getProducts() {
+		List<Product> products = productRepository.findAll();
+
+		return ProductMapper.toProductsResponse(products);
+	}
+}

src/main/java/com/moabam/api/domain/entity/Product.java

@@ -0,0 +1,74 @@
+package com.moabam.api.domain.entity;
+
+import static com.moabam.global.error.model.ErrorMessage.*;
+import static java.util.Objects.*;
+
+import org.hibernate.annotations.ColumnDefault;
+
+import com.moabam.api.domain.entity.enums.ProductType;
+import com.moabam.global.common.entity.BaseTimeEntity;
+import com.moabam.global.error.exception.BadRequestException;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.AccessLevel;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@Table(name = "product")
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+public class Product extends BaseTimeEntity {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.IDENTITY)
+	@Column(name = "id")
+	private Long id;
+
+	@Enumerated(value = EnumType.STRING)
+	@Column(name = "type", nullable = false)
+	@ColumnDefault("'BUG'")
+	private ProductType type;
+
+	@Column(name = "name", nullable = false)
+	private String name;
+
+	@Column(name = "price", nullable = false)
+	private int price;
+
+	@Column(name = "quantity", nullable = false)
+	@ColumnDefault("1")
+	private int quantity;
+
+	@Builder
+	private Product(ProductType type, String name, int price, Integer quantity) {
+		this.type = requireNonNullElse(type, ProductType.BUG);
+		this.name = requireNonNull(name);
+		this.price = validatePrice(price);
+		this.quantity = validateQuantity(requireNonNullElse(quantity, 1));
+	}
+
+	private int validatePrice(int price) {
+		if (price < 0) {
+			throw new BadRequestException(INVALID_PRICE);
+		}
+
+		return price;
+	}
+
+	private int validateQuantity(int quantity) {
+		if (quantity < 1) {
+			throw new BadRequestException(INVALID_QUANTITY);
+		}
+
+		return quantity;
+	}
+}

src/main/java/com/moabam/api/domain/entity/enums/ProductType.java

@@ -0,0 +1,6 @@
+package com.moabam.api.domain.entity.enums;
+
+public enum ProductType {
+
+	BUG;
+}

src/main/java/com/moabam/api/domain/repository/ProductRepository.java

@@ -0,0 +1,9 @@
+package com.moabam.api.domain.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import com.moabam.api.domain.entity.Product;
+
+public interface ProductRepository extends JpaRepository<Product, Long> {
+
+}

src/main/java/com/moabam/api/dto/ProductMapper.java

@@ -0,0 +1,30 @@
+package com.moabam.api.dto;
+
+import java.util.List;
+
+import com.moabam.api.domain.entity.Product;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+public final class ProductMapper {
+
+	public static ProductResponse toProductResponse(Product product) {
+		return ProductResponse.builder()
+			.id(product.getId())
+			.type(product.getType().name())
+			.name(product.getName())
+			.price(product.getPrice())
+			.quantity(product.getQuantity())
+			.build();
+	}
+
+	public static ProductsResponse toProductsResponse(List<Product> products) {
+		return ProductsResponse.builder()
+			.products(products.stream()
+				.map(ProductMapper::toProductResponse)
+				.toList())
+			.build();
+	}
+}

src/main/java/com/moabam/api/dto/ProductResponse.java

@@ -0,0 +1,14 @@
+package com.moabam.api.dto;
+
+import lombok.Builder;
+
+@Builder
+public record ProductResponse(
+	Long id,
+	String type,
+	String name,
+	int price,
+	int quantity
+) {
+
+}

src/main/java/com/moabam/api/dto/ProductsResponse.java

@@ -0,0 +1,12 @@
+package com.moabam.api.dto;
+
+import java.util.List;
+
+import lombok.Builder;
+
+@Builder
+public record ProductsResponse(
+	List<ProductResponse> products
+) {
+
+}

src/main/java/com/moabam/api/presentation/ProductController.java

@@ -0,0 +1,24 @@
+package com.moabam.api.presentation;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.moabam.api.application.ProductService;
+import com.moabam.api.dto.ProductsResponse;
+
+import lombok.RequiredArgsConstructor;
+
+@RestController
+@RequestMapping("/products")
+@RequiredArgsConstructor
+public class ProductController {
+
+	private final ProductService productService;
+
+	@GetMapping
+	public ResponseEntity<ProductsResponse> getProducts() {
+		return ResponseEntity.ok(productService.getProducts());
+	}
+}

src/main/java/com/moabam/global/error/model/ErrorMessage.java

@@ -17,7 +17,9 @@ public enum ErrorMessage {
 
 	MEMBER_NOT_FOUND("존재하지 않는 회원입니다."),
 
-	INVALID_BUG_COUNT("벌레 개수는 0 이상이어야 합니다.");
+	INVALID_BUG_COUNT("벌레 개수는 0 이상이어야 합니다."),
+	INVALID_PRICE("가격은 0 이상이어야 합니다."),
+	INVALID_QUANTITY("수량은 1 이상이어야 합니다.");
 
 	private final String message;
 }

src/test/java/com/moabam/api/application/ProductServiceTest.java

@@ -0,0 +1,48 @@
+package com.moabam.api.application;
+
+import static com.moabam.fixture.ProductFixture.*;
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.BDDMockito.*;
+
+import java.util.List;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import com.moabam.api.domain.entity.Product;
+import com.moabam.api.domain.repository.ProductRepository;
+import com.moabam.api.dto.ProductResponse;
+import com.moabam.api.dto.ProductsResponse;
+
+@ExtendWith(MockitoExtension.class)
+class ProductServiceTest {
+
+	@InjectMocks
+	ProductService productService;
+
+	@Mock
+	ProductRepository productRepository;
+
+	@DisplayName("상품 목록을 조회한다.")
+	@Test
+	void get_products_success() {
+		// given
+		Product product1 = bugProduct();
+		Product product2 = bugProduct();
+		given(productRepository.findAll()).willReturn(List.of(product1, product2));
+
+		// when
+		ProductsResponse response = productService.getProducts();
+
+		// then
+		List<String> productNames = response.products().stream()
+			.map(ProductResponse::name)
+			.toList();
+		assertThat(response.products()).hasSize(2);
+		assertThat(productNames).containsOnly(BUG_PRODUCT_NAME, BUG_PRODUCT_NAME);
+	}
+}

src/test/java/com/moabam/api/domain/entity/ProductTest.java

@@ -0,0 +1,36 @@
+package com.moabam.api.domain.entity;
+
+import static org.assertj.core.api.AssertionsForClassTypes.*;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import com.moabam.global.error.exception.BadRequestException;
+
+class ProductTest {
+
+	@DisplayName("상품 가격이 0 보다 작으면 예외가 발생한다.")
+	@Test
+	void validate_price_exception() {
+		Product.ProductBuilder productBuilder = Product.builder()
+			.name("X10")
+			.price(-10);
+
+		assertThatThrownBy(productBuilder::build)
+			.isInstanceOf(BadRequestException.class)
+			.hasMessage("가격은 0 이상이어야 합니다.");
+	}
+
+	@DisplayName("상품량이 1 보다 작으면 예외가 발생한다.")
+	@Test
+	void validate_quantity_exception() {
+		Product.ProductBuilder productBuilder = Product.builder()
+			.name("X10")
+			.price(1000)
+			.quantity(-1);
+
+		assertThatThrownBy(productBuilder::build)
+			.isInstanceOf(BadRequestException.class)
+			.hasMessage("수량은 1 이상이어야 합니다.");
+	}
+}

src/test/java/com/moabam/api/presentation/ProductControllerTest.java

@@ -0,0 +1,59 @@
+package com.moabam.api.presentation;
+
+import static java.nio.charset.StandardCharsets.*;
+import static org.mockito.BDDMockito.*;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
+import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.*;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+import java.util.List;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.web.servlet.MockMvc;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.moabam.api.application.ProductService;
+import com.moabam.api.domain.entity.Product;
+import com.moabam.api.dto.ProductMapper;
+import com.moabam.api.dto.ProductsResponse;
+import com.moabam.fixture.ProductFixture;
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class ProductControllerTest {
+
+	@Autowired
+	MockMvc mockMvc;
+
+	@Autowired
+	ObjectMapper objectMapper;
+
+	@MockBean
+	ProductService productService;
+
+	@DisplayName("상품 목록을 조회한다.")
+	@Test
+	void get_products_success() throws Exception {
+		// given
+		Product product1 = ProductFixture.bugProduct();
+		Product product2 = ProductFixture.bugProduct();
+		ProductsResponse expected = ProductMapper.toProductsResponse(List.of(product1, product2));
+		given(productService.getProducts()).willReturn(expected);
+
+		// when & then
+		String content = mockMvc.perform(get("/products"))
+			.andDo(print())
+			.andExpect(status().isOk())
+			.andReturn()
+			.getResponse()
+			.getContentAsString(UTF_8);
+		ProductsResponse actual = objectMapper.readValue(content, ProductsResponse.class);
+		Assertions.assertThat(actual).isEqualTo(expected);
+	}
+}

src/test/java/com/moabam/fixture/ProductFixture.java

@@ -0,0 +1,20 @@
+package com.moabam.fixture;
+
+import com.moabam.api.domain.entity.Product;
+import com.moabam.api.domain.entity.enums.ProductType;
+
+public class ProductFixture {
+
+	public static final String BUG_PRODUCT_NAME = "X10";
+	public static final int BUG_PRODUCT_PRICE = 3000;
+	public static final int BUG_PRODUCT_QUANTITY = 10;
+
+	public static Product bugProduct() {
+		return Product.builder()
+			.type(ProductType.BUG)
+			.name(BUG_PRODUCT_NAME)
+			.price(BUG_PRODUCT_PRICE)
+			.quantity(BUG_PRODUCT_QUANTITY)
+			.build();
+	}
+}