[#9] 주문 도메인 모델 구현

docs/order_diagram.mermaid

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+erDiagram
+    Order {
+    %% 고객의 주문 단위
+    }
+    OrderLine {
+    %% 주문에 포함된 개별 주문 항목
+    }
+    Order ||--o{ OrderLine: "주문 - 주문 항목 (1:N)"

src/main/kotlin/com/nilgil/commerce/common/StringListConverter.kt

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+package com.nilgil.commerce.common
+
+import jakarta.persistence.AttributeConverter
+import jakarta.persistence.Converter
+
+@Converter
+class StringListConverter : AttributeConverter<List<String>, String> {
+    companion object {
+        const val DELIMITER = ","
+    }
+
+    override fun convertToDatabaseColumn(attribute: List<String>?): String? {
+        if (attribute.isNullOrEmpty()) {
+            return null
+        }
+        return attribute.joinToString(DELIMITER)
+    }
+
+    override fun convertToEntityAttribute(dbData: String?): List<String> {
+        if (dbData.isNullOrBlank()) {
+            return emptyList()
+        }
+        return dbData.split(DELIMITER).map { it.trim() }
+    }
+}

src/main/kotlin/com/nilgil/commerce/order/Order.kt

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+package com.nilgil.commerce.order
+
+import com.nilgil.commerce.common.BaseEntity
+import jakarta.persistence.Column
+import jakarta.persistence.Entity
+import jakarta.persistence.EnumType
+import jakarta.persistence.Enumerated
+import jakarta.persistence.Table
+
+@Entity
+@Table(name = "orders")
+class Order(
+    @Column(unique = true)
+    val code: String,
+    val totalAmount: Int,
+    val userId: Long,
+) : BaseEntity() {
+    @Enumerated(EnumType.STRING)
+    var status: OrderStatus = OrderStatus.CREATED
+
+    var paymentId: Long? = null
+
+    fun pay(paymentId: Long) {
+        if (this.status != OrderStatus.CREATED) {
+            throw IllegalStateException("결제를 진행할 수 없는 상태입니다.")
+        }
+        this.paymentId = paymentId
+        this.status = OrderStatus.PAID
+    }
+
+    fun complete() {
+        if (this.status != OrderStatus.PAID) {
+            throw IllegalStateException("완료 처리할 수 없는 상태입니다.")
+        }
+        this.status = OrderStatus.COMPLETED
+    }
+
+    fun cancel() {
+        if (this.status != OrderStatus.CREATED && this.status != OrderStatus.PAID) {
+            throw IllegalStateException("취소할 수 없는 상태입니다.")
+        }
+        this.status = OrderStatus.CANCELLED
+    }
+
+    fun returnOrder() {
+        if (this.status != OrderStatus.COMPLETED) {
+            throw IllegalStateException("반품할 수 없는 상태입니다.")
+        }
+        this.status = OrderStatus.RETURNED
+    }
+}

src/main/kotlin/com/nilgil/commerce/order/OrderItem.kt

@@ -0,0 +1,25 @@
+package com.nilgil.commerce.order
+
+import com.nilgil.commerce.common.StringListConverter
+import jakarta.persistence.Column
+import jakarta.persistence.Convert
+import jakarta.persistence.Embeddable
+
+@Embeddable
+data class OrderItem(
+    @Column(name = "item_title")
+    val title: String,
+    @Convert(converter = StringListConverter::class)
+    @Column(name = "item_options")
+    val options: List<String> = listOf(),
+    @Column(name = "item_price")
+    val price: Int,
+    @Column(name = "item_thumbnail_image_url")
+    val thumbnailImageUrl: String? = null,
+    @Column(name = "product_item_id")
+    val productItemId: Long,
+) {
+    init {
+        require(price >= 0) { "가격은 0 이상이어야 합니다." }
+    }
+}

src/main/kotlin/com/nilgil/commerce/order/OrderLine.kt

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+package com.nilgil.commerce.order
+
+import com.nilgil.commerce.common.BaseEntity
+import jakarta.persistence.Embedded
+import jakarta.persistence.Entity
+import jakarta.persistence.FetchType
+import jakarta.persistence.ManyToOne
+
+@Entity
+class OrderLine(
+    @Embedded
+    val item: OrderItem,
+    val quantity: Int,
+    @ManyToOne(fetch = FetchType.LAZY)
+    val order: Order,
+) : BaseEntity() {
+    init {
+        require(quantity >= 1) { "수량은 1개 이상이어야 합니다." }
+    }
+
+    fun getTotalPrice(): Int = item.price * quantity
+}

src/main/kotlin/com/nilgil/commerce/order/OrderStatus.kt

@@ -0,0 +1,9 @@
+package com.nilgil.commerce.order
+
+enum class OrderStatus {
+    CREATED,
+    PAID,
+    COMPLETED,
+    CANCELLED,
+    RETURNED,
+}

src/test/kotlin/com/nilgil/commerce/order/OrderFixtures.kt

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+package com.nilgil.commerce.order
+
+import org.mockito.Mockito.mock
+
+object OrderFixtures {
+    fun anOrder(
+        code: String = "TEST-ORDER-CODE-12345",
+        totalAmount: Int = 0,
+        userId: Long = 1L,
+    ): Order =
+        Order(
+            code = code,
+            totalAmount = totalAmount,
+            userId = userId,
+        )
+
+    fun anOrderLine(
+        order: Order = mock(Order::class.java),
+        quantity: Int = 1,
+        item: OrderItem = anOrderItem(),
+    ): OrderLine =
+        OrderLine(
+            order = order,
+            quantity = quantity,
+            item = item,
+        )
+
+    fun anOrderItem(
+        title: String = "테스트 상품",
+        options: List<String> = listOf("옵션1", "옵션2"),
+        price: Int = 10000,
+        productItemId: Long = 1L,
+    ): OrderItem =
+        OrderItem(
+            title = title,
+            options = options,
+            price = price,
+            productItemId = productItemId,
+            thumbnailImageUrl = "http://test.image/1",
+        )
+}

src/test/kotlin/com/nilgil/commerce/order/OrderItemTest.kt

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+package com.nilgil.commerce.order
+
+import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatIllegalArgumentException
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+
+class OrderItemTest {
+    @Nested
+    @DisplayName("객체 생성 시")
+    inner class DescribeCreation {
+        @Test
+        fun `가격이 음수이면 IllegalArgumentException이 발생한다`() {
+            // when, then
+            assertThatIllegalArgumentException()
+                .isThrownBy {
+                    OrderFixtures.anOrderItem(price = -10000)
+                }
+        }
+
+        @Test
+        fun `가격이 0 또는 양수이면 정상적으로 생성된다`() {
+            // when
+            val itemWithZeroPrice = OrderFixtures.anOrderItem(price = 0)
+            val itemWithPositivePrice = OrderFixtures.anOrderItem(price = 10000)
+
+            // then
+            assertThat(itemWithZeroPrice).isNotNull
+            assertThat(itemWithPositivePrice).isNotNull
+        }
+    }
+}

src/test/kotlin/com/nilgil/commerce/order/OrderLineTest.kt

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+package com.nilgil.commerce.order
+
+import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatIllegalArgumentException
+import org.junit.jupiter.api.DisplayName
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.CsvSource
+
+class OrderLineTest {
+    @Nested
+    @DisplayName("객체 생성 시")
+    inner class DescribeCreation {
+        @CsvSource("0", "-1", Integer.MIN_VALUE.toString())
+        @ParameterizedTest
+        fun `수량이 0 또는 음수이면 IllegalArgumentException이 발생한다`(quantity: Int) {
+            // when, then
+            assertThatIllegalArgumentException()
+                .isThrownBy {
+                    OrderFixtures.anOrderLine(quantity = quantity)
+                }
+        }
+
+        @CsvSource("1", Integer.MAX_VALUE.toString())
+        @ParameterizedTest
+        fun `수량이 양수이면 정상적으로 생성된다`(quantity: Int) {
+            // when
+            val orderLine = OrderFixtures.anOrderLine(quantity = quantity)
+
+            // then
+            assertThat(orderLine).isNotNull
+            assertThat(orderLine.quantity).isEqualTo(quantity)
+        }
+    }
+
+    @Nested
+    @DisplayName("총액 조회 시")
+    inner class DescribeGetTotalPrice {
+        @Test
+        fun `아이템 가격과 수량을 곱한 총액을 반환한다`() {
+            // given
+            val price = 15000
+            val item = OrderFixtures.anOrderItem(price = price)
+
+            val quantity = 3
+            val orderLine = OrderFixtures.anOrderLine(item = item, quantity = quantity)
+
+            // when
+            val totalPrice = orderLine.getTotalPrice()
+
+            // then
+            assertThat(totalPrice).isEqualTo(price * quantity)
+        }
+    }
+}