chap03 : 테스트 작성 순서 연습 #31

이상민/src/test/java/chap03/ExpiryDateCalculator.java

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+package chap03;
+
+import java.time.LocalDate;
+import java.time.YearMonth;
+
+public class ExpiryDateCalculator {
+    public LocalDate calculateExpiryDate(PayData payData) {
+        int addedMonths = payData.getPayAmount() == 100_000 ? 12 : payData.getPayAmount() / 10_000;
+
+        if(payData.getFirstBillingDate() != null){
+            return expiryDateUsingFirstBillingDate(payData,addedMonths);
+        }else{
+            return payData.getBillingDate().plusMonths(addedMonths);
+        }
+    }
+
+    private LocalDate expiryDateUsingFirstBillingDate(PayData payData, int addedMonths){
+        LocalDate candidateExp = payData.getBillingDate().plusMonths(addedMonths); // 후보 만료일
+        final int dayOfFirstBilling = payData.getFirstBillingDate().getDayOfMonth();
+
+        if(dayOfFirstBilling != candidateExp.getDayOfMonth()){ // 첫 납부일의 일자와 후보 만료일의 일자가 다르면
+            final int dayLenOfCandiMon = YearMonth.from(candidateExp).lengthOfMonth();
+            if(dayLenOfCandiMon < dayOfFirstBilling){  // 후보 만료일이 포함된 달의 마지막 날 < 첫 납부일의 일자
+                return candidateExp.withDayOfMonth(dayLenOfCandiMon);
+            }
+            return candidateExp.withDayOfMonth(dayOfFirstBilling); // 첫 납부일의 일자를 후보 만료일의 일자로 사용
+        }else{
+            return candidateExp;
+        }
+    }
+}

이상민/src/test/java/chap03/ExpiryDateCalculatorTest.java

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+package chap03;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDate;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ExpiryDateCalculatorTest {  // expiry(expiration) date : 만료일
+
+    @Test
+    void 십만원을_납부하면_1년_제공(){
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 1, 28))
+                        .payAmount(100_000)
+                        .build()
+                , LocalDate.of(2020, 1, 28));
+    }
+
+    // 1만원을 납부하면 한 달 뒤 같은 날을 만료일로 계산
+    @Test
+    void 만원_납부하면_한달_뒤가_만료일이_됨() {
+//        // 처음 작성하는 코드
+//        assertEquals(기대하는 만료일, 실제 만료일);
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 3, 1))
+                        .payAmount(10_000)
+                        .build()
+                , LocalDate.of(2019, 4, 1));
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 5, 5))
+                        .payAmount(10_000)
+                        .build()
+                , LocalDate.of(2019, 6, 5));
+    }
+
+    private void assertExpiryDate(PayData payData, LocalDate expectedExpiryDate) {
+        ExpiryDateCalculator cal = new ExpiryDateCalculator();
+        LocalDate realExpiryDate = cal.calculateExpiryDate(payData);
+        assertEquals(expectedExpiryDate, realExpiryDate);
+    }
+
+    @Test
+    void 납부일과_한달_뒤_일자가_같지_않음() {
+        // LocalDate#plusMonths() 메서드가 알아서 한 달 추가 처리를 해 줌
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 1, 31))
+                        .payAmount(10_000)
+                        .build()
+                , LocalDate.of(2019, 2, 28));
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 5, 31))
+                        .payAmount(10_000)
+                        .build()
+                , LocalDate.of(2019, 6, 30));
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2020, 1, 31))
+                        .payAmount(10_000)
+                        .build()
+                , LocalDate.of(2020, 2, 29));
+    }
+
+    @Test
+    void 첫_납부일과_만료일_일자가_다를때_만원_납부(){
+        // case 1
+        PayData payData = PayData.builder()
+                .firstBillingData(LocalDate.of(2019, 1, 31))  // 첫 납부일
+                .billingDate(LocalDate.of(2019, 2, 28)) // 납부일
+                .payAmount(10_000)
+                .build();
+        assertExpiryDate(payData, LocalDate.of(2019, 3, 31));
+
+        // case 2
+        PayData payData2 = PayData.builder()
+                .firstBillingData(LocalDate.of(2019, 1, 30))  // 첫 납부일
+                .billingDate(LocalDate.of(2019, 2, 28)) // 납부일
+                .payAmount(10_000)
+                .build();
+        assertExpiryDate(payData2, LocalDate.of(2019, 3, 30));
+
+        // case 3
+        PayData payData3 = PayData.builder()
+                .firstBillingData(LocalDate.of(2019, 5, 31))  // 첫 납부일
+                .billingDate(LocalDate.of(2019, 6, 30)) // 납부일
+                .payAmount(10_000)
+                .build();
+        assertExpiryDate(payData3, LocalDate.of(2019, 7, 31));
+
+    }
+
+    @Test
+    void 이만원_이상_납부하면_비례해서_만료일_계산(){
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 3, 1))
+                        .payAmount(20_000)
+                        .build()
+                , LocalDate.of(2019, 5, 1));
+        assertExpiryDate(
+                PayData.builder()
+                        .billingDate(LocalDate.of(2019, 3, 1))
+                        .payAmount(30_000)
+                        .build()
+                , LocalDate.of(2019, 6, 1));
+    }
+
+    @Test
+    void 첫_납부일과_만료일_일자가_다를때_이만원_이상_납부(){
+        // case 1
+        assertExpiryDate(
+                PayData.builder()
+                        .firstBillingData(LocalDate.of(2019, 1, 31))  // 첫 납부일
+                        .billingDate(LocalDate.of(2019, 2, 28)) // 납부일
+                        .payAmount(20_000)
+                        .build()
+                , LocalDate.of(2019, 4, 30));
+
+        // case 2
+        assertExpiryDate(
+                PayData.builder()
+                        .firstBillingData(LocalDate.of(2019, 3, 31))  // 첫 납부일
+                        .billingDate(LocalDate.of(2019, 4, 30)) // 납부일
+                        .payAmount(30_000)
+                        .build()
+                , LocalDate.of(2019, 7, 31));
+    }
+}

이상민/src/test/java/chap03/PayData.java

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+package chap03;
+
+import java.time.LocalDate;
+
+public class PayData {
+
+    private LocalDate firstBillingDate;
+    private LocalDate billingDate;
+    private int payAmount;
+
+    private PayData() {
+    }
+
+    public PayData(LocalDate firstBillingDate, LocalDate billingDate, int payAmount) {
+        this.firstBillingDate = firstBillingDate;
+        this.billingDate = billingDate;
+        this.payAmount = payAmount;
+    }
+    public LocalDate getFirstBillingDate() {
+        return firstBillingDate;
+    }
+    public LocalDate getBillingDate() {
+        return billingDate;
+    }
+    public int getPayAmount() {
+        return payAmount;
+    }
+
+    public static Builder builder(){
+        return new Builder();
+    }
+
+    // 간단한 빌더 패턴 적용한 것임
+    public static class Builder {
+        private PayData data = new PayData();
+
+        public Builder firstBillingData(LocalDate firstBillingDate) {
+            data.firstBillingDate = firstBillingDate;
+            return this;
+        }
+
+        public Builder billingDate(LocalDate billingDate) {
+            data.billingDate = billingDate;
+            return this;
+        }
+
+        public Builder payAmount(int payAmount) {
+            data.payAmount = payAmount;
+            return this;
+        }
+
+        public PayData build(){
+            return data;
+        }
+
+
+    }
+
+}