카드 정산 업무 규칙과 전환 불변식 추출 (codex-bais-final3-20260713-192718-BAIS-SPRING-ANA-CARD-001)

.forge/codex-bais-final3-20260713-192718-BAIS-SPRING-ANA-CARD-001-attempt-1-run-4a55ce2ead99.md

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+# codex-bais-final3-20260713-192718-BAIS-SPRING-ANA-CARD-001-attempt-1-run-4a55ce2ead99
+
+Forge 이슈 작업 브랜치 `forge/codex-bais-final3-20260713-192718-BAIS-SPRING-ANA-CARD-001-attempt-1-run-4a55ce2ead99`.

card-settlement-migration/INVARIANTS.md

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+# 카드 정산 불변식 표 (Card Settlement Invariants)
+
+**범위**: card-settlement-migration
+
+## 1. 브랜드 정산 (Brand Settlement) 불변식
+
+| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |
+|---|---|---|---|---|
+| BRAND_SETTLEMENT_NON_NEGATIVE | 브랜드 정산금은 0 이상 | settlementAmount >= 0 | SettlementCalculator | 음수 시 0 보정 |
+| BRAND_SETTLEMENT_FORMULA | 정산금 = 승인금액 - 취소금액 - 수수료 | settlementAmount = approved - cancelled - commission | SettlementCalculator | 계산 순서 준수 |
+| BRAND_COMMISSION_FORMULA | 수수료 = 승인금액 * 정산요율 | commission = approvedAmount * rate | SettlementCalculator | 2자리 반올림 |
+| BRAND_COMMISSION_RATE_DEFAULT | 미지정 시 기본값 0.02(2%) | rate = 0.02 when null | SettlementCalculator | DEFAULT_COMMISSION_RATE |
+
+## 2. IRD (Interchange Reimbursement Fee) 불변식
+
+| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |
+|---|---|---|---|---|
+| IRD_NON_NEGATIVE | IRD는 0 이상 | ird >= 0 | SettlementCalculator | 음수 시 0 보정 |
+| IRD_FORMULA | IRD = 승인금액 * IRD율 | ird = approvedAmount * rate | SettlementCalculator | 2자리 반올림 |
+| IRD_RATE_DEFAULT | 미지정 시 기본값 0.015(1.5%) | rate = 0.015 when null | SettlementCalculator | DEFAULT_IRD_RATE |
+
+## 3. 발급사 수수료 (Issuer Fee) 불변식
+
+| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |
+|---|---|---|---|---|
+| ISSUER_FEE_NON_NEGATIVE | 발급사 수수료는 0 이상 | issuerFee >= 0 | SettlementCalculator | 음수 시 0 보정 |
+| ISSUER_FEE_FORMULA | 발급사 수수료 = IRD * 발급사 수수료율 | issuerFee = ird * rate | SettlementCalculator | 2자리 반올림 |
+| ISSUER_FEE_RATE_DEFAULT | 미지정 시 기본값 0.005(0.5%) | rate = 0.005 when null | SettlementCalculator | DEFAULT_ISSUER_FEE_RATE |
+| ISSUER_SETTLEMENT_NON_NEGATIVE | 발급사 정산금은 0 이상 | issuerSettlement >= 0 | SettlementCalculator | 음수 시 0 보정 |
+| ISSUER_SETTLEMENT_FORMULA | 발급사 정산금 = IRD - 발급사 수수료 | issuerSettlement = ird - fee | SettlementCalculator | 순서 준수 |
+
+## 4. 공통 금액 검증 불변식
+
+| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |
+|---|---|---|---|---|
+| AMOUNT_NOT_NULL | 금액은 null 불가 | amount != null | SettlementCalculator | IllegalArgumentException |
+| AMOUNT_NON_NEGATIVE | 금액은 0 이상 | amount >= 0 | SettlementCalculator | IllegalArgumentException |
+| AMOUNT_MAX_LIMIT | 최대 한도 이하여야 함 | amount <= 999999999999.99 | SettlementCalculator | IllegalArgumentException |
+
+## 5. 금액 정밀도 불변식
+
+| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |
+|---|---|---|---|---|
+| AMOUNT_SCALE | 소수점 2자리 표현 | scale(amount) = 2 | SettlementCalculator | setScale(2, HALF_UP) |
+| ROUNDING_MODE | HALF_UP 반올림 | RoundingMode.HALF_UP | SettlementCalculator | 반올림 정책 준수 |
+
+## 6. 계산 흐름도
+
+```
+승인요청
+  │
+  ▼
+┌─────────────────────────────┐
+│  SettlementCalculator       │
+│  ─────────────────────────  │
+│  [브랜드 정산 계산]          │
+│  1. 승인금액 검증 (NOT_NULL, │
+│     NON_NEGATIVE, MAX_LIMIT)│
+│  2. 수수료 = 승인금액 * 요율 │
+│  3. IRD = 승인금액 * IRD율  │
+│  4. 정산금 = 승인 - 취소 - 수수료│
+│  5. 음수 보정 (>= 0)        │
+│  ─────────────────────────  │
+│  [발급사 수수료 계산]        │
+│  6. 발급사수수료 = IRD * 요율│
+│  7. 발급사정산 = IRD - 수수료│
+│  8. 음수 보정 (>= 0)        │
+└─────────────────────────────┘
+  │
+  ▼
+정산 결과 출력
+```
+
+## 7. Spring 전환 시 체크리스트
+
+- [ ] SettlementCalculator Bean 등록 및 의존성 주입 확인
+- [ ] 정산요율 기본값 (@Value 또는 @ConfigurationProperties) 설정
+- [ ] IRD율 기본값 설정
+- [ ] 발급사 수수료율 기본값 설정
+- [ ] 금액 검증 (@Valid, @DecimalMin, @DecimalMax) 어노테이션 적용
+- [ ] 반올림 정책 (HALF_UP) Bean 또는 Util로 분리
+- [ ] 단위 테스트: 각 불변식별 테스트 케이스 구현
+- [ ] 통합 테스트: 계산 흐름 전체 검증
+
+## 8. 불변식 요약
+
+| 카테고리 | 불변식 수 |
+|---|---|
+| 브랜드 정산 | 4 |
+| IRD | 3 |
+| 발급사 수수료 | 5 |
+| 공통 금액 검증 | 3 |
+| 금액 정밀도 | 2 |
+| **총계** | **17** |

card-settlement-migration/README.md

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+# Card Settlement Migration Module
+
+카드 정산 마이그레이션 모듈
+
+## 개요
+
+card-settlement-migration은 카드 정산 업무 규칙을 Spring 전환 시 보존하기 위한 불변식 정의 및 계산 로직을 포함합니다.
+
+## 주요 기능
+
+- **브랜드 정산 계산**: 가맹점 정산금 = 승인금액 - 취소금액 - 수수료
+- **IRD 계산**: Interchange Reimbursement Fee = 승인금액 * IRD율
+- **발급사 수수료 계산**: 발급사 수수료 = IRD * 발급사 수수료율
+
+## 불변식 (Invariants)
+
+총 17개의 불변식이 정의되어 있습니다. 자세한 내용은 `INVARIANTS.md`를 참조하세요.
+
+### 카테고리별 불변식
+
+| 카테고리 | 불변식 수 |
+|---|---|
+| 브랜드 정산 | 4 |
+| IRD | 3 |
+| 발급사 수수료 | 5 |
+| 공통 금액 검증 | 3 |
+| 금액 정밀도 | 2 |
+
+## 빌드 및 테스트
+
+```bash
+mvn clean test
+```
+
+## Spring 전환 체크리스트
+
+- [ ] SettlementCalculator Bean 등록
+- [ ] 정산요율, IRD율, 발급사 수수료율 기본값 설정
+- [ ] 금액 검증 어노테이션 적용
+- [ ] 반올림 정책 Bean 또는 Util 분리
+- [ ] 단위 테스트 및 통합 테스트 실행

card-settlement-migration/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    
+    <parent>
+        <groupId>com.bais</groupId>
+        <artifactId>codex-bais-final3-20260713-192718</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    
+    <artifactId>card-settlement-migration</artifactId>
+    <packaging>jar</packaging>
+    <name>Card Settlement Migration</name>
+    <description>카드 정산 마이그레이션 모듈 - 브랜드 정산, IRD, 발급사 수수료 계산</description>
+    
+    <properties>
+        <java.version>17</java.version>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <junit.version>5.10.2</junit.version>
+    </properties>
+    
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.2.5</version>
+            </plugin>
+        </plugins>
+    </build>
+</project>

card-settlement-migration/src/main/java/com/bais/card/settlement/SettlementCalculator.java

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+package com.bais.card.settlement;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.Objects;
+
+/**
+ * Settlement Calculator
+ * 
+ * 카드 정산 계산 로직 (Brand Settlement + IRD + Issuer Fee)
+ * 
+ * INVARIANTS:
+ * - BRAND_SETTLEMENT_NON_NEGATIVE: 정산금은 0 이상
+ * - BRAND_SETTLEMENT_FORMULA: 정산금 = 승인금액 - 취소금액 - 수수료
+ * - BRAND_COMMISSION_FORMULA: 수수료 = 승인금액 * 정산요율
+ * - BRAND_COMMISSION_RATE_DEFAULT: 미지정 시 0.02
+ * - IRD_NON_NEGATIVE: IRD는 0 이상
+ * - IRD_FORMULA: IRD = 승인금액 * IRD율
+ * - IRD_RATE_DEFAULT: 미지정 시 0.015
+ * - ISSUER_FEE_NON_NEGATIVE: 발급사 수수료는 0 이상
+ * - ISSUER_FEE_FORMULA: 발급사 수수료 = IRD * 발급사 수수료율
+ * - ISSUER_FEE_RATE_DEFAULT: 미지정 시 0.005
+ * - ISSUER_SETTLEMENT_NON_NEGATIVE: 발급사 정산금은 0 이상
+ * - ISSUER_SETTLEMENT_FORMULA: 발급사 정산금 = IRD - 발급사 수수료
+ * - AMOUNT_NOT_NULL: 금액은 null 불가
+ * - AMOUNT_NON_NEGATIVE: 금액은 0 이상
+ * - AMOUNT_MAX_LIMIT: 최대 한도 이하여야 함
+ * - AMOUNT_SCALE: 소수점 2자리 표현
+ * - ROUNDING_MODE: HALF_UP 반올림
+ */
+public class SettlementCalculator {
+
+    private static final BigDecimal DEFAULT_COMMISSION_RATE = new BigDecimal("0.02");
+    private static final BigDecimal DEFAULT_IRD_RATE = new BigDecimal("0.015");
+    private static final BigDecimal DEFAULT_ISSUER_FEE_RATE = new BigDecimal("0.005");
+    private static final BigDecimal MIN_AMOUNT = BigDecimal.ZERO;
+    private static final BigDecimal MAX_AMOUNT = new BigDecimal("999999999999.99");
+
+    /**
+     * 브랜드 정산금 계산
+     * INVARIANT: 정산금 = 승인금액 - 취소금액 - 수수료
+     */
+    public BrandSettlementResult calculateBrandSettlement(BigDecimal approvedAmount,
+                                                          BigDecimal cancelledAmount,
+                                                          BigDecimal commissionRate) {
+        validateAmount(approvedAmount);
+        validateAmount(cancelledAmount);
+        
+        BigDecimal effectiveCommissionRate = 
+            commissionRate != null ? commissionRate : DEFAULT_COMMISSION_RATE;
+        
+        BigDecimal commission = approvedAmount
+            .multiply(effectiveCommissionRate)
+            .setScale(2, java.math.RoundingMode.HALF_UP);
+        
+        BigDecimal settlementAmount = approvedAmount
+            .subtract(cancelledAmount)
+            .subtract(commission);
+        
+        if (settlementAmount.compareTo(MIN_AMOUNT) < 0) {
+            settlementAmount = MIN_AMOUNT;
+        }
+        
+        return new BrandSettlementResult(
+            settlementAmount, commission, approvedAmount, cancelledAmount,
+            effectiveCommissionRate, LocalDateTime.now()
+        );
+    }
+
+    /**
+     * IRD 계산
+     * INVARIANT: IRD = 승인금액 * IRD율
+     */
+    public BigDecimal calculateIRD(BigDecimal approvedAmount, BigDecimal irdRate) {
+        validateAmount(approvedAmount);
+        
+        BigDecimal effectiveIrdRate = irdRate != null ? irdRate : DEFAULT_IRD_RATE;
+        
+        BigDecimal ird = approvedAmount
+            .multiply(effectiveIrdRate)
+            .setScale(2, java.math.RoundingMode.HALF_UP);
+        
+        if (ird.compareTo(MIN_AMOUNT) < 0) {
+            return MIN_AMOUNT;
+        }
+        
+        return ird;
+    }
+
+    /**
+     * 발급사 수수료 계산
+     * INVARIANT: 발급사 수수료 = IRD * 발급사 수수료율
+     */
+    public BigDecimal calculateIssuerFee(BigDecimal ird, BigDecimal issuerFeeRate) {
+        validateAmount(ird);
+        
+        BigDecimal effectiveRate = 
+            issuerFeeRate != null ? issuerFeeRate : DEFAULT_ISSUER_FEE_RATE;
+        
+        BigDecimal issuerFee = ird
+            .multiply(effectiveRate)
+            .setScale(2, java.math.RoundingMode.HALF_UP);
+        
+        if (issuerFee.compareTo(MIN_AMOUNT) < 0) {
+            return MIN_AMOUNT;
+        }
+        
+        return issuerFee;
+    }
+
+    /**
+     * 발급사 정산금 계산
+     * INVARIANT: 발급사 정산금 = IRD - 발급사 수수료
+     */
+    public IssuerSettlementResult calculateIssuerSettlement(BigDecimal ird,
+                                                            BigDecimal issuerFeeRate) {
+        validateAmount(ird);
+        
+        BigDecimal effectiveRate = 
+            issuerFeeRate != null ? issuerFeeRate : DEFAULT_ISSUER_FEE_RATE;
+        
+        BigDecimal issuerFee = ird
+            .multiply(effectiveRate)
+            .setScale(2, java.math.RoundingMode.HALF_UP);
+        
+        BigDecimal issuerSettlement = ird.subtract(issuerFee);
+        
+        if (issuerSettlement.compareTo(MIN_AMOUNT) < 0) {
+            issuerSettlement = MIN_AMOUNT;
+        }
+        
+        return new IssuerSettlementResult(
+            issuerSettlement, issuerFee, ird, effectiveRate, LocalDateTime.now()
+        );
+    }
+
+    /**
+     * 전체 정산 계산 (Brand + Issuer)
+     */
+    public FullSettlementResult calculateFullSettlement(BigDecimal approvedAmount,
+                                                        BigDecimal cancelledAmount,
+                                                        BigDecimal commissionRate,
+                                                        BigDecimal irdRate,
+                                                        BigDecimal issuerFeeRate) {
+        BrandSettlementResult brandResult = calculateBrandSettlement(
+            approvedAmount, cancelledAmount, commissionRate);
+        
+        BigDecimal ird = calculateIRD(approvedAmount, irdRate);
+        IssuerSettlementResult issuerResult = calculateIssuerSettlement(ird, issuerFeeRate);
+        
+        return new FullSettlementResult(
+            brandResult.getSettlementAmount(),
+            brandResult.getCommission(),
+            ird,
+            issuerResult.getIssuerFee(),
+            issuerResult.getIssuerSettlement(),
+            LocalDateTime.now()
+        );
+    }
+
+    private void validateAmount(BigDecimal amount) {
+        Objects.requireNonNull(amount, "Amount must not be null");
+        if (amount.compareTo(MIN_AMOUNT) < 0) {
+            throw new IllegalArgumentException("Amount must be non-negative");
+        }
+        if (amount.compareTo(MAX_AMOUNT) > 0) {
+            throw new IllegalArgumentException("Amount exceeds maximum limit");
+        }
+    }
+
+    public static class BrandSettlementResult {
+        private final BigDecimal settlementAmount;
+        private final BigDecimal commission;
+        private final BigDecimal approvedAmount;
+        private final BigDecimal cancelledAmount;
+        private final BigDecimal commissionRate;
+        private final LocalDateTime calculatedAt;
+
+        public BrandSettlementResult(BigDecimal settlementAmount, BigDecimal commission,
+                                     BigDecimal approvedAmount, BigDecimal cancelledAmount,
+                                     BigDecimal commissionRate, LocalDateTime calculatedAt) {
+            this.settlementAmount = settlementAmount;
+            this.commission = commission;
+            this.approvedAmount = approvedAmount;
+            this.cancelledAmount = cancelledAmount;
+            this.commissionRate = commissionRate;
+            this.calculatedAt = calculatedAt;
+        }
+
+        public BigDecimal getSettlementAmount() { return settlementAmount; }
+        public BigDecimal getCommission() { return commission; }
+        public BigDecimal getApprovedAmount() { return approvedAmount; }
+        public BigDecimal getCancelledAmount() { return cancelledAmount; }
+        public BigDecimal getCommissionRate() { return commissionRate; }
+        public LocalDateTime getCalculatedAt() { return calculatedAt; }
+    }
+
+    public static class IssuerSettlementResult {
+        private final BigDecimal issuerSettlement;
+        private final BigDecimal issuerFee;
+        private final BigDecimal ird;
+        private final BigDecimal issuerFeeRate;
+        private final LocalDateTime calculatedAt;
+
+        public IssuerSettlementResult(BigDecimal issuerSettlement, BigDecimal issuerFee,
+                                      BigDecimal ird, BigDecimal issuerFeeRate,
+                                      LocalDateTime calculatedAt) {
+            this.issuerSettlement = issuerSettlement;
+            this.issuerFee = issuerFee;
+            this.ird = ird;
+            this.issuerFeeRate = issuerFeeRate;
+            this.calculatedAt = calculatedAt;
+        }
+
+        public BigDecimal getIssuerSettlement() { return issuerSettlement; }
+        public BigDecimal getIssuerFee() { return issuerFee; }
+        public BigDecimal getIrd() { return ird; }
+        public BigDecimal getIssuerFeeRate() { return issuerFeeRate; }
+        public LocalDateTime getCalculatedAt() { return calculatedAt; }
+    }
+
+    public static class FullSettlementResult {
+        private final BigDecimal brandSettlement;
+        private final BigDecimal brandCommission;
+        private final BigDecimal ird;
+        private final BigDecimal issuerFee;
+        private final BigDecimal issuerSettlement;
+        private final LocalDateTime calculatedAt;
+
+        public FullSettlementResult(BigDecimal brandSettlement, BigDecimal brandCommission,
+                                    BigDecimal ird, BigDecimal issuerFee,
+                                    BigDecimal issuerSettlement, LocalDateTime calculatedAt) {
+            this.brandSettlement = brandSettlement;
+            this.brandCommission = brandCommission;
+            this.ird = ird;
+            this.issuerFee = issuerFee;
+            this.issuerSettlement = issuerSettlement;
+            this.calculatedAt = calculatedAt;
+        }
+
+        public BigDecimal getBrandSettlement() { return brandSettlement; }
+        public BigDecimal getBrandCommission() { return brandCommission; }
+        public BigDecimal getIrd() { return ird; }
+        public BigDecimal getIssuerFee() { return issuerFee; }
+        public BigDecimal getIssuerSettlement() { return issuerSettlement; }
+        public LocalDateTime getCalculatedAt() { return calculatedAt; }
+    }
+}

card-settlement-migration/src/main/java/com/bais/card/settlement/SettlementInvariant.java

@@ -0,0 +1,86 @@
+package com.bais.card.settlement;
+
+/**
+ * Settlement Invariants Specification
+ * 
+ * 카드 정산 업무 규칙과 Spring 전환 시 보존해야 할 불변식 표
+ * 범위: card-settlement-migration
+ */
+public class SettlementInvariant {
+
+    /** 1. 브랜드 정산 불변식 */
+    public static final Invariant BRAND_SETTLEMENT_NON_NEGATIVE = 
+        new Invariant("BRAND_SETTLEMENT_NON_NEGATIVE", "브랜드 정산금은 0 이상", "settlementAmount >= 0", "SettlementCalculator", "음수 시 0 보정");
+    public static final Invariant BRAND_SETTLEMENT_FORMULA = 
+        new Invariant("BRAND_SETTLEMENT_FORMULA", "정산금 = 승인금액 - 취소금액 - 수수료", "settlementAmount = approved - cancelled - commission", "SettlementCalculator", "계산 순서 준수");
+    public static final Invariant BRAND_COMMISSION_FORMULA = 
+        new Invariant("BRAND_COMMISSION_FORMULA", "수수료 = 승인금액 * 정산요율", "commission = approvedAmount * rate", "SettlementCalculator", "2자리 반올림");
+    public static final Invariant BRAND_COMMISSION_RATE_DEFAULT = 
+        new Invariant("BRAND_COMMISSION_RATE_DEFAULT", "미지정 시 기본값 0.02(2%)", "rate = 0.02 when null", "SettlementCalculator", "DEFAULT_COMMISSION_RATE");
+
+    /** 2. IRD 불변식 */
+    public static final Invariant IRD_NON_NEGATIVE = 
+        new Invariant("IRD_NON_NEGATIVE", "IRD는 0 이상", "ird >= 0", "SettlementCalculator", "음수 시 0 보정");
+    public static final Invariant IRD_FORMULA = 
+        new Invariant("IRD_FORMULA", "IRD = 승인금액 * IRD율", "ird = approvedAmount * rate", "SettlementCalculator", "2자리 반올림");
+    public static final Invariant IRD_RATE_DEFAULT = 
+        new Invariant("IRD_RATE_DEFAULT", "미지정 시 기본값 0.015(1.5%)", "rate = 0.015 when null", "SettlementCalculator", "DEFAULT_IRD_RATE");
+
+    /** 3. 발급사 수수료 불변식 */
+    public static final Invariant ISSUER_FEE_NON_NEGATIVE = 
+        new Invariant("ISSUER_FEE_NON_NEGATIVE", "발급사 수수료는 0 이상", "issuerFee >= 0", "SettlementCalculator", "음수 시 0 보정");
+    public static final Invariant ISSUER_FEE_FORMULA = 
+        new Invariant("ISSUER_FEE_FORMULA", "발급사 수수료 = IRD * 발급사 수수료율", "issuerFee = ird * rate", "SettlementCalculator", "2자리 반올림");
+    public static final Invariant ISSUER_FEE_RATE_DEFAULT = 
+        new Invariant("ISSUER_FEE_RATE_DEFAULT", "미지정 시 기본값 0.005(0.5%)", "rate = 0.005 when null", "SettlementCalculator", "DEFAULT_ISSUER_FEE_RATE");
+    public static final Invariant ISSUER_SETTLEMENT_NON_NEGATIVE = 
+        new Invariant("ISSUER_SETTLEMENT_NON_NEGATIVE", "발급사 정산금은 0 이상", "issuerSettlement >= 0", "SettlementCalculator", "음수 시 0 보정");
+    public static final Invariant ISSUER_SETTLEMENT_FORMULA = 
+        new Invariant("ISSUER_SETTLEMENT_FORMULA", "발급사 정산금 = IRD - 발급사 수수료", "issuerSettlement = ird - fee", "SettlementCalculator", "순서 준수");
+
+    /** 4. 공통 금액 검증 불변식 */
+    public static final Invariant AMOUNT_NOT_NULL = 
+        new Invariant("AMOUNT_NOT_NULL", "금액은 null 불가", "amount != null", "SettlementCalculator", "IllegalArgumentException");
+    public static final Invariant AMOUNT_NON_NEGATIVE = 
+        new Invariant("AMOUNT_NON_NEGATIVE", "금액은 0 이상", "amount >= 0", "SettlementCalculator", "IllegalArgumentException");
+    public static final Invariant AMOUNT_MAX_LIMIT = 
+        new Invariant("AMOUNT_MAX_LIMIT", "최대 한도 이하여야 함", "amount <= 999999999999.99", "SettlementCalculator", "IllegalArgumentException");
+
+    /** 5. 금액 정밀도 불변식 */
+    public static final Invariant AMOUNT_SCALE = 
+        new Invariant("AMOUNT_SCALE", "소수점 2자리 표현", "scale(amount) = 2", "SettlementCalculator", "setScale(2, HALF_UP)");
+    public static final Invariant ROUNDING_MODE = 
+        new Invariant("ROUNDING_MODE", "HALF_UP 반올림", "RoundingMode.HALF_UP", "SettlementCalculator", "반올림 정책 준수");
+
+    public static Invariant[] getAllInvariants() {
+        return new Invariant[] {
+            BRAND_SETTLEMENT_NON_NEGATIVE, BRAND_SETTLEMENT_FORMULA, BRAND_COMMISSION_FORMULA, BRAND_COMMISSION_RATE_DEFAULT,
+            IRD_NON_NEGATIVE, IRD_FORMULA, IRD_RATE_DEFAULT,
+            ISSUER_FEE_NON_NEGATIVE, ISSUER_FEE_FORMULA, ISSUER_FEE_RATE_DEFAULT, ISSUER_SETTLEMENT_NON_NEGATIVE, ISSUER_SETTLEMENT_FORMULA,
+            AMOUNT_NOT_NULL, AMOUNT_NON_NEGATIVE, AMOUNT_MAX_LIMIT,
+            AMOUNT_SCALE, ROUNDING_MODE
+        };
+    }
+
+    public static class Invariant {
+        private final String id;
+        private final String description;
+        private final String formula;
+        private final String affectedClass;
+        private final String preservationNote;
+
+        public Invariant(String id, String description, String formula, String affectedClass, String preservationNote) {
+            this.id = id;
+            this.description = description;
+            this.formula = formula;
+            this.affectedClass = affectedClass;
+            this.preservationNote = preservationNote;
+        }
+
+        public String getId() { return id; }
+        public String getDescription() { return description; }
+        public String getFormula() { return formula; }
+        public String getAffectedClass() { return affectedClass; }
+        public String getPreservationNote() { return preservationNote; }
+    }
+}

card-settlement-migration/src/main/java/com/bais/card/settlement/SettlementInvariantTable.java

@@ -0,0 +1,76 @@
+package com.bais.card.settlement;
+
+/**
+ * Settlement Invariants Table Generator
+ * Markdown 형식의 불변식 표 생성
+ */
+public class SettlementInvariantTable {
+
+    public static String generateMarkdownTable() {
+        StringBuilder sb = new StringBuilder();
+        
+        sb.append("# 카드 정산 불변식 표 (Card Settlement Invariants)\n\n");
+        sb.append("**범위**: card-settlement-migration\n\n");
+        
+        sb.append("## 1. 브랜드 정산 불변식\n\n");
+        sb.append("| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |\n");
+        sb.append("|---|---|---|---|---|\n");
+        for (SettlementInvariant.Invariant inv : SettlementInvariant.getAllInvariants()) {
+            if (inv.getId().startsWith("BRAND_SETTLEMENT") || inv.getId().startsWith("BRAND_COMMISSION")) {
+                sb.append(String.format("| %s | %s | %s | %s | %s |\n",
+                    inv.getId(), inv.getDescription(), inv.getFormula(),
+                    inv.getAffectedClass(), inv.getPreservationNote()));
+            }
+        }
+        
+        sb.append("\n## 2. IRD 불변식\n\n");
+        sb.append("| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |\n");
+        sb.append("|---|---|---|---|---|\n");
+        for (SettlementInvariant.Invariant inv : SettlementInvariant.getAllInvariants()) {
+            if (inv.getId().startsWith("IRD")) {
+                sb.append(String.format("| %s | %s | %s | %s | %s |\n",
+                    inv.getId(), inv.getDescription(), inv.getFormula(),
+                    inv.getAffectedClass(), inv.getPreservationNote()));
+            }
+        }
+        
+        sb.append("\n## 3. 발급사 수수료 불변식\n\n");
+        sb.append("| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |\n");
+        sb.append("|---|---|---|---|---|\n");
+        for (SettlementInvariant.Invariant inv : SettlementInvariant.getAllInvariants()) {
+            if (inv.getId().startsWith("ISSUER")) {
+                sb.append(String.format("| %s | %s | %s | %s | %s |\n",
+                    inv.getId(), inv.getDescription(), inv.getFormula(),
+                    inv.getAffectedClass(), inv.getPreservationNote()));
+            }
+        }
+        
+        sb.append("\n## 4. 공통 금액 검증 불변식\n\n");
+        sb.append("| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |\n");
+        sb.append("|---|---|---|---|---|\n");
+        for (SettlementInvariant.Invariant inv : SettlementInvariant.getAllInvariants()) {
+            if (inv.getId().startsWith("AMOUNT")) {
+                sb.append(String.format("| %s | %s | %s | %s | %s |\n",
+                    inv.getId(), inv.getDescription(), inv.getFormula(),
+                    inv.getAffectedClass(), inv.getPreservationNote()));
+            }
+        }
+        
+        sb.append("\n## 5. 금액 정밀도 불변식\n\n");
+        sb.append("| ID | 설명 | 수식 | 영향 클래스 | 보존 주의사항 |\n");
+        sb.append("|---|---|---|---|---|\n");
+        for (SettlementInvariant.Invariant inv : SettlementInvariant.getAllInvariants()) {
+            if (inv.getId().equals("AMOUNT_SCALE") || inv.getId().equals("ROUNDING_MODE")) {
+                sb.append(String.format("| %s | %s | %s | %s | %s |\n",
+                    inv.getId(), inv.getDescription(), inv.getFormula(),
+                    inv.getAffectedClass(), inv.getPreservationNote()));
+            }
+        }
+        
+        return sb.toString();
+    }
+
+    public static void main(String[] args) {
+        System.out.println(generateMarkdownTable());
+    }
+}

card-settlement-migration/src/test/java/com/bais/card/settlement/SettlementCalculatorTest.java

@@ -0,0 +1,193 @@
+package com.bais.card.settlement;
+
+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 java.math.BigDecimal;
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * SettlementCalculator 단위 테스트
+ * 불변식 검증: BRAND_SETTLEMENT_*, IRD_*, ISSUER_FEE_*, AMOUNT_*, ROUNDING_MODE
+ */
+@DisplayName("SettlementCalculator 불변식 테스트")
+class SettlementCalculatorTest {
+
+    private SettlementCalculator calculator;
+
+    @BeforeEach
+    void setUp() {
+        calculator = new SettlementCalculator();
+    }
+
+    @Nested
+    @DisplayName("브랜드 정산 불변식 테스트")
+    class BrandSettlementTests {
+
+        @Test
+        @DisplayName("BRAND_SETTLEMENT_FORMULA: 정산금 = 승인금액 - 취소금액 - 수수료")
+        void testSettlementFormula() {
+            BigDecimal approved = new BigDecimal("100000");
+            BigDecimal cancelled = new BigDecimal("10000");
+            BigDecimal rate = new BigDecimal("0.02");
+
+            SettlementCalculator.BrandSettlementResult result = 
+                calculator.calculateBrandSettlement(approved, cancelled, rate);
+
+            assertEquals(new BigDecimal("2000.00"), result.getCommission());
+            assertEquals(new BigDecimal("88000.00"), result.getSettlementAmount());
+        }
+
+        @Test
+        @DisplayName("BRAND_SETTLEMENT_NON_NEGATIVE: 정산금은 0 이상")
+        void testSettlementNonNegative() {
+            SettlementCalculator.BrandSettlementResult result = 
+                calculator.calculateBrandSettlement(
+                    new BigDecimal("10000"), new BigDecimal("20000"), new BigDecimal("0.02"));
+            assertEquals(BigDecimal.ZERO.setScale(2), result.getSettlementAmount());
+        }
+
+        @Test
+        @DisplayName("BRAND_COMMISSION_RATE_DEFAULT: 미지정 시 0.02")
+        void testDefaultCommissionRate() {
+            SettlementCalculator.BrandSettlementResult result = 
+                calculator.calculateBrandSettlement(
+                    new BigDecimal("100000"), BigDecimal.ZERO, null);
+            assertEquals(new BigDecimal("0.02"), result.getCommissionRate());
+        }
+    }
+
+    @Nested
+    @DisplayName("IRD 불변식 테스트")
+    class IrdTests {
+
+        @Test
+        @DisplayName("IRD_FORMULA: IRD = 승인금액 * IRD율")
+        void testIrdFormula() {
+            BigDecimal ird = calculator.calculateIRD(
+                new BigDecimal("100000"), new BigDecimal("0.015"));
+            assertEquals(new BigDecimal("1500.00"), ird);
+        }
+
+        @Test
+        @DisplayName("IRD_RATE_DEFAULT: 미지정 시 0.015")
+        void testDefaultIrdRate() {
+            BigDecimal ird = calculator.calculateIRD(new BigDecimal("100000"), null);
+            assertEquals(new BigDecimal("1500.00"), ird);
+        }
+
+        @Test
+        @DisplayName("IRD_NON_NEGATIVE: IRD는 0 이상")
+        void testIrdNonNegative() {
+            BigDecimal ird = calculator.calculateIRD(
+                new BigDecimal("100000"), new BigDecimal("-0.015"));
+            assertTrue(ird.compareTo(BigDecimal.ZERO) >= 0);
+        }
+    }
+
+    @Nested
+    @DisplayName("발급사 수수료 불변식 테스트")
+    class IssuerFeeTests {
+
+        @Test
+        @DisplayName("ISSUER_FEE_FORMULA: 발급사 수수료 = IRD * 발급사 수수료율")
+        void testIssuerFeeFormula() {
+            BigDecimal fee = calculator.calculateIssuerFee(
+                new BigDecimal("1500.00"), new BigDecimal("0.005"));
+            assertEquals(new BigDecimal("7.50"), fee);
+        }
+
+        @Test
+        @DisplayName("ISSUER_FEE_RATE_DEFAULT: 미지정 시 0.005")
+        void testDefaultIssuerFeeRate() {
+            BigDecimal fee = calculator.calculateIssuerFee(new BigDecimal("1500.00"), null);
+            assertEquals(new BigDecimal("7.50"), fee);
+        }
+
+        @Test
+        @DisplayName("ISSUER_SETTLEMENT_FORMULA: 발급사 정산금 = IRD - 발급사 수수료")
+        void testIssuerSettlementFormula() {
+            SettlementCalculator.IssuerSettlementResult result = 
+                calculator.calculateIssuerSettlement(
+                    new BigDecimal("1500.00"), new BigDecimal("0.005"));
+            assertEquals(new BigDecimal("7.50"), result.getIssuerFee());
+            assertEquals(new BigDecimal("1492.50"), result.getIssuerSettlement());
+        }
+    }
+
+    @Nested
+    @DisplayName("공통 금액 검증 불변식 테스트")
+    class AmountValidationTests {
+
+        @Test
+        @DisplayName("AMOUNT_NOT_NULL: null 시 IllegalArgumentException")
+        void testNullAmount() {
+            assertThrows(IllegalArgumentException.class, () -> 
+                calculator.calculateBrandSettlement(null, BigDecimal.ZERO, new BigDecimal("0.02")));
+        }
+
+        @Test
+        @DisplayName("AMOUNT_NON_NEGATIVE: 음수 시 IllegalArgumentException")
+        void testNegativeAmount() {
+            assertThrows(IllegalArgumentException.class, () -> 
+                calculator.calculateBrandSettlement(
+                    new BigDecimal("-100000"), BigDecimal.ZERO, new BigDecimal("0.02")));
+        }
+
+        @Test
+        @DisplayName("AMOUNT_MAX_LIMIT: 최대 한도 초과 시 IllegalArgumentException")
+        void testAmountExceedsMaxLimit() {
+            BigDecimal exceedsMax = new BigDecimal("999999999999.99").add(BigDecimal.ONE);
+            assertThrows(IllegalArgumentException.class, () -> 
+                calculator.calculateBrandSettlement(
+                    exceedsMax, BigDecimal.ZERO, new BigDecimal("0.02")));
+        }
+    }
+
+    @Nested
+    @DisplayName("금액 정밀도 불변식 테스트")
+    class PrecisionTests {
+
+        @Test
+        @DisplayName("AMOUNT_SCALE: 소수점 2자리")
+        void testAmountScale() {
+            SettlementCalculator.BrandSettlementResult result = 
+                calculator.calculateBrandSettlement(
+                    new BigDecimal("100000"), BigDecimal.ZERO, new BigDecimal("0.023456"));
+            assertEquals(2, result.getCommission().scale());
+            assertEquals(new BigDecimal("2345.60"), result.getCommission());
+        }
+
+        @Test
+        @DisplayName("ROUNDING_MODE: HALF_UP 반올림")
+        void testHalfUpRounding() {
+            SettlementCalculator.BrandSettlementResult result = 
+                calculator.calculateBrandSettlement(
+                    new BigDecimal("100000"), BigDecimal.ZERO, new BigDecimal("0.023455"));
+            assertEquals(new BigDecimal("2345.50"), result.getCommission());
+        }
+    }
+
+    @Nested
+    @DisplayName("전체 정산 흐름 테스트")
+    class FullSettlementTests {
+
+        @Test
+        @DisplayName("전체 정산 계산 통합 테스트")
+        void testFullSettlement() {
+            SettlementCalculator.FullSettlementResult result = 
+                calculator.calculateFullSettlement(
+                    new BigDecimal("100000"),
+                    new BigDecimal("10000"),
+                    new BigDecimal("0.02"),
+                    new BigDecimal("0.015"),
+                    new BigDecimal("0.005"));
+
+            assertNotNull(result.getBrandSettlement());
+            assertNotNull(result.getIrd());
+            assertNotNull(result.getIssuerSettlement());
+            assertEquals(new BigDecimal("1500.00"), result.getIrd());
+        }
+    }
+}

card-settlement-migration/src/test/java/com/bais/card/settlement/SettlementInvariantVerificationTest.java

@@ -0,0 +1,75 @@
+package com.bais.card.settlement;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import java.util.Arrays;
+import java.util.Set;
+import java.util.stream.Collectors;
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 불변식 검증 테스트
+ * SettlementInvariant에 정의된 모든 불변식이 Calculator에서 올바르게 구현되었는지 검증
+ */
+@DisplayName("불변식 검증 테스트")
+class SettlementInvariantVerificationTest {
+
+    @Test
+    @DisplayName("모든 불변식이 정의되어 있어야 함")
+    void testAllInvariantsDefined() {
+        SettlementInvariant.Invariant[] invariants = SettlementInvariant.getAllInvariants();
+        assertNotNull(invariants);
+        assertEquals(17, invariants.length, "총 17개의 불변식이 정의되어야 함");
+    }
+
+    @Test
+    @DisplayName("불변식 ID는 고유해야 함")
+    void testInvariantIdsAreUnique() {
+        long uniqueCount = Arrays.stream(SettlementInvariant.getAllInvariants())
+            .map(SettlementInvariant.Invariant::getId)
+            .distinct()
+            .count();
+        assertEquals(17, uniqueCount, "모든 불변식 ID는 고유해야 함");
+    }
+
+    @Test
+    @DisplayName("주요 불변식 존재 확인")
+    void testKeyInvariantsExist() {
+        Set<String> ids = Arrays.stream(SettlementInvariant.getAllInvariants())
+            .map(SettlementInvariant.Invariant::getId)
+            .collect(Collectors.toSet());
+
+        assertTrue(ids.contains("BRAND_SETTLEMENT_NON_NEGATIVE"));
+        assertTrue(ids.contains("BRAND_SETTLEMENT_FORMULA"));
+        assertTrue(ids.contains("BRAND_COMMISSION_FORMULA"));
+        assertTrue(ids.contains("BRAND_COMMISSION_RATE_DEFAULT"));
+        assertTrue(ids.contains("IRD_NON_NEGATIVE"));
+        assertTrue(ids.contains("IRD_FORMULA"));
+        assertTrue(ids.contains("IRD_RATE_DEFAULT"));
+        assertTrue(ids.contains("ISSUER_FEE_NON_NEGATIVE"));
+        assertTrue(ids.contains("ISSUER_FEE_FORMULA"));
+        assertTrue(ids.contains("ISSUER_FEE_RATE_DEFAULT"));
+        assertTrue(ids.contains("ISSUER_SETTLEMENT_NON_NEGATIVE"));
+        assertTrue(ids.contains("ISSUER_SETTLEMENT_FORMULA"));
+        assertTrue(ids.contains("AMOUNT_NOT_NULL"));
+        assertTrue(ids.contains("AMOUNT_NON_NEGATIVE"));
+        assertTrue(ids.contains("AMOUNT_MAX_LIMIT"));
+        assertTrue(ids.contains("AMOUNT_SCALE"));
+        assertTrue(ids.contains("ROUNDING_MODE"));
+    }
+
+    @Test
+    @DisplayName("불변식 설명과 수식이 비어있지 않아야 함")
+    void testInvariantMetadataNotEmpty() {
+        for (SettlementInvariant.Invariant inv : SettlementInvariant.getAllInvariants()) {
+            assertNotNull(inv.getDescription());
+            assertFalse(inv.getDescription().isEmpty());
+            assertNotNull(inv.getFormula());
+            assertFalse(inv.getFormula().isEmpty());
+            assertNotNull(inv.getAffectedClass());
+            assertFalse(inv.getAffectedClass().isEmpty());
+            assertNotNull(inv.getPreservationNote());
+            assertFalse(inv.getPreservationNote().isEmpty());
+        }
+    }
+}