5.move inner classes to upper level.

src/test/java/com/ejoongseok/wmslive/product/feature/Category.java

@@ -0,0 +1,10 @@
+package com.ejoongseok.wmslive.product.feature;
+
+public enum Category {
+    ELECTRONICS("전자 제품");
+    private final String description;
+
+    Category(final String description) {
+        this.description = description;
+    }
+}

src/test/java/com/ejoongseok/wmslive/product/feature/Product.java

@@ -0,0 +1,81 @@
+package com.ejoongseok.wmslive.product.feature;
+
+import org.springframework.util.Assert;
+
+public class Product {
+
+    private final String name;
+    private final String code;
+    private final String description;
+    private final String brand;
+    private final String maker;
+    private final String origin;
+    private final Category category;
+    private final TemperatureZone temperatureZone;
+    private final Long weightInGrams;
+    private final ProductSize productSize;
+    @lombok.Getter
+    private Long id;
+
+    public Product(
+            final String name,
+            final String code,
+            final String description,
+            final String brand,
+            final String maker,
+            final String origin,
+            final Category category,
+            final TemperatureZone temperatureZone,
+            final Long weightInGrams,
+            final ProductSize productSize) {
+        validateConstructor(
+                name,
+                code,
+                description,
+                brand,
+                maker,
+                origin,
+                category,
+                temperatureZone,
+                weightInGrams,
+                productSize);
+        this.name = name;
+        this.code = code;
+        this.description = description;
+        this.brand = brand;
+        this.maker = maker;
+        this.origin = origin;
+        this.category = category;
+        this.temperatureZone = temperatureZone;
+        this.weightInGrams = weightInGrams;
+        this.productSize = productSize;
+    }
+
+    private void validateConstructor(
+            final String name,
+            final String code,
+            final String description,
+            final String brand,
+            final String maker,
+            final String origin,
+            final Category category,
+            final TemperatureZone temperatureZone,
+            final Long weightInGrams,
+            final ProductSize productSize) {
+        Assert.hasText(name, "상품명은 필수입니다.");
+        Assert.hasText(code, "상품코드는 필수입니다.");
+        Assert.hasText(description, "상품설명은 필수입니다.");
+        Assert.hasText(brand, "브랜드는 필수입니다.");
+        Assert.hasText(maker, "제조사는 필수입니다.");
+        Assert.hasText(origin, "원산지는 필수입니다.");
+        Assert.notNull(category, "카테고리는 필수입니다.");
+        Assert.notNull(temperatureZone, "온도대는 필수입니다.");
+        Assert.notNull(weightInGrams, "무게는 필수입니다.");
+        Assert.notNull(productSize, "상품크기는 필수입니다.");
+    }
+
+    public void assignId(final Long id) {
+        this.id = id;
+    }
+
+}

src/test/java/com/ejoongseok/wmslive/product/feature/ProductRepository.java

@@ -0,0 +1,21 @@
+package com.ejoongseok.wmslive.product.feature;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class ProductRepository {
+    private final Map<Long, Product> products = new HashMap<>();
+    private Long nextId = 1L;
+
+    public void save(final Product product) {
+        product.assignId(nextId);
+        nextId++;
+        products.put(product.getId(), product);
+    }
+
+    public List<Product> findAll() {
+        return new ArrayList<>(products.values());
+    }
+}

src/test/java/com/ejoongseok/wmslive/product/feature/ProductSize.java

@@ -0,0 +1,40 @@
+package com.ejoongseok.wmslive.product.feature;
+
+import org.springframework.util.Assert;
+
+public class ProductSize {
+    private final Long widthInMillimeters;
+    private final Long heightInMillimeters;
+    private final Long lengthInMillimeters;
+
+    public ProductSize(
+            final Long widthInMillimeters,
+            final Long heightInMillimeters,
+            final Long lengthInMillimeters) {
+        validateProductSize(
+                widthInMillimeters,
+                heightInMillimeters,
+                lengthInMillimeters);
+        this.widthInMillimeters = widthInMillimeters;
+        this.heightInMillimeters = heightInMillimeters;
+        this.lengthInMillimeters = lengthInMillimeters;
+    }
+
+    private void validateProductSize(
+            final Long widthInMillimeters,
+            final Long heightInMillimeters,
+            final Long lengthInMillimeters) {
+        Assert.notNull(widthInMillimeters, "가로길이는 필수입니다.");
+        if (0 > widthInMillimeters) {
+            throw new IllegalArgumentException("가로길이는 0보다 작을 수 없습니다.");
+        }
+        Assert.notNull(heightInMillimeters, "세로길이는 필수입니다.");
+        if (0 > heightInMillimeters) {
+            throw new IllegalArgumentException("세로길이는 0보다 작을 수 없습니다.");
+        }
+        Assert.notNull(lengthInMillimeters, "세로길이는 필수입니다.");
+        if (0 > lengthInMillimeters) {
+            throw new IllegalArgumentException("세로길이는 0보다 작을 수 없습니다.");
+        }
+    }
+}

src/test/java/com/ejoongseok/wmslive/product/feature/RegisterProduct.java

@@ -0,0 +1,77 @@
+package com.ejoongseok.wmslive.product.feature;
+
+import org.springframework.util.Assert;
+
+public class RegisterProduct {
+    private final ProductRepository productRepository;
+
+    public RegisterProduct(final ProductRepository productRepository) {
+        this.productRepository = productRepository;
+    }
+
+    public void request(final Request request) {
+        final Product product = request.toDomain();
+        productRepository.save(product);
+    }
+
+    public record Request(
+            String name,
+            String code,
+            String description,
+            String brand,
+            String maker,
+            String origin,
+            Category category,
+            TemperatureZone temperatureZone,
+            Long weightInGrams,
+            Long widthInMillimeters,
+            Long heightInMillimeters,
+            Long lengthInMillimeters) {
+
+        public Request {
+            Assert.hasText(name, "상품명은 필수입니다.");
+            Assert.hasText(code, "상품코드는 필수입니다.");
+            Assert.hasText(description, "상품설명은 필수입니다.");
+            Assert.hasText(brand, "브랜드는 필수입니다.");
+            Assert.hasText(maker, "제조사는 필수입니다.");
+            Assert.hasText(origin, "원산지는 필수입니다.");
+            Assert.notNull(category, "카테고리는 필수입니다.");
+            Assert.notNull(temperatureZone, "온도대는 필수입니다.");
+            Assert.notNull(weightInGrams, "무게는 필수입니다.");
+            if (0 > weightInGrams) {
+                throw new IllegalArgumentException("무게는 0보다 작을 수 없습니다.");
+            }
+            Assert.notNull(widthInMillimeters, "가로길이는 필수입니다.");
+            if (0 > widthInMillimeters) {
+                throw new IllegalArgumentException("가로길이는 0보다 작을 수 없습니다.");
+            }
+            Assert.notNull(heightInMillimeters, "세로길이는 필수입니다.");
+            if (0 > heightInMillimeters) {
+                throw new IllegalArgumentException("세로길이는 0보다 작을 수 없습니다.");
+            }
+            Assert.notNull(lengthInMillimeters, "세로길이는 필수입니다.");
+            if (0 > lengthInMillimeters) {
+                throw new IllegalArgumentException("세로길이는 0보다 작을 수 없습니다.");
+            }
+        }
+
+        public Product toDomain() {
+            return new Product(
+                    name,
+                    code,
+                    description,
+                    brand,
+                    maker,
+                    origin,
+                    category,
+                    temperatureZone,
+                    weightInGrams,
+                    new ProductSize(
+                            widthInMillimeters,
+                            heightInMillimeters,
+                            lengthInMillimeters)
+            );
+        }
+
+    }
+}