spring core : 할인정책 변경(OCP, DIP 위반)

spring-core/basic/src/main/java/com/example/basic/discount/RateDiscountPolicy.java

@@ -0,0 +1,18 @@
+package com.example.basic.discount;
+
+import com.example.basic.member.Grade;
+import com.example.basic.member.Member;
+
+public class RateDiscountPolicy implements DiscountPolicy {
+
+    private final int discountPercent = 10;
+
+    @Override
+    public int discount(Member member, int price) {
+        if (member.getGrade() == Grade.VIP) {
+            return price * discountPercent / 100;
+        } else {
+            return 0;
+        }
+    }
+}

spring-core/basic/src/main/java/com/example/basic/order/OrderServiceImpl.java

@@ -2,6 +2,7 @@ package com.example.basic.order;
 
 import com.example.basic.discount.DiscountPolicy;
 import com.example.basic.discount.FixDiscountPolicy;
+import com.example.basic.discount.RateDiscountPolicy;
 import com.example.basic.member.Member;
 import com.example.basic.member.MemberRepository;
 import com.example.basic.member.MemoryMemberRepository;
@@ -9,7 +10,8 @@ import com.example.basic.member.MemoryMemberRepository;
 public class OrderServiceImpl implements OrderService {
 
     private final MemberRepository memberRepository = new MemoryMemberRepository();
-    private final DiscountPolicy discountPolicy = new FixDiscountPolicy();
+//    private final DiscountPolicy discountPolicy = new FixDiscountPolicy();
+    private final DiscountPolicy discountPolicy = new RateDiscountPolicy();
 
     @Override
     public Order createOrder(Long memberId, String itemName, int itemPrice) {

spring-core/basic/src/test/java/com/example/basic/discount/RateDiscountPolicyTest.java

@@ -0,0 +1,35 @@
+package com.example.basic.discount;
+
+import com.example.basic.member.Grade;
+import com.example.basic.member.Member;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class RateDiscountPolicyTest {
+    
+    RateDiscountPolicy discountPolicy = new RateDiscountPolicy();
+    
+    @Test
+    @DisplayName("VIP는 10% 할인이 적용되어야 한다.")
+    void vip_o() {
+        //given
+        Member member = new Member(1L, "memberVIP", Grade.VIP);
+        //when
+        int discount = discountPolicy.discount(member, 10000);
+        //then
+        assertThat(discount).isEqualTo(1000);
+    }
+
+    @Test
+    @DisplayName("VIP가 아니면 할인이 적용되지 않아야 한다.")
+    void vip_x() {
+        //given
+        Member member = new Member(1L, "memberVIP", Grade.BASIC);
+        //when
+        int discount = discountPolicy.discount(member, 10000);
+        //then
+        assertThat(discount).isEqualTo(0);
+    }
+}