테스트 코드 작성 (assertj, junit5)

testImplementation 'org.junit.jupiter:junit-jupiter-api:5.7.0'
testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.0'
testImplementation('org.assertj:assertj-core:3.22.0')

import org.junit.jupiter.api.BeforeEach;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.init.DatabasePopulatorUtils;
import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;