Merge pull request #138 from daadaadaah/fix/add-validationAmountIsPos…

…itive

`InventoryCommandRepository`에 amount 양수 검증 추가

src/main/java/com/hcommerce/heecommerce/inventory/AmountIsNotPositiveException.java

@@ -0,0 +1,7 @@
+package com.hcommerce.heecommerce.inventory;
+
+public class AmountIsNotPositiveException extends RuntimeException {
+    public AmountIsNotPositiveException() {
+        super("수량이 양수인지 확인해주세요");
+    }
+}

src/main/java/com/hcommerce/heecommerce/inventory/InventoryCommandRepository.java

@@ -31,14 +31,24 @@ public void delete(UUID dealProductUuid) {
     }
 
     public int decreaseByAmount(UUID dealProductUuid, int amount) {
+        validationAmountIsPositive(amount);
+
         String key = super.getRedisKey(dealProductUuid);
 
         return (int) redisStringsRepository.decreaseByAmount(key, Long.valueOf(amount));
     }
 
     public void increaseByAmount(UUID dealProductUuid, int amount) {
+        validationAmountIsPositive(amount);
+
         String key = super.getRedisKey(dealProductUuid);
 
         redisStringsRepository.increaseByAmount(key, Long.valueOf(amount));
     }
+
+    private void validationAmountIsPositive(int amount) {
+        if(amount <= 0) {
+            throw new AmountIsNotPositiveException();
+        }
+    }
 }