Modify. demo/ItemRepositoryTest.java -> demo/repository/ItemRepositoryTest.java

src/test/java/com/example/demo/ItemRepositoryTest.java → src/test/java/com/example/demo/repository/ItemRepositoryTest.java

-package com.example.demo;
+package com.example.demo.repository;
 import org.junit.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;