[SOLVED] Spring boot test cases failed - java.lang.IllegalStateException: Failed to load ApplicationContext

I am new to Spring Boot, and I'm using Spring Boot 3.2.8. I'm having a tough time debugging a repository test. It seems like there is a problem with the application context in the test and its complexity. What could be the problem? And how do you identify a problem?

build.gradle

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.2.8'
    id 'io.spring.dependency-management' version '1.1.6'
}

group = '***.*******'
version = '0.0.1-SNAPSHOT'

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(17)
    }
}

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    implementation 'org.springframework.boot:spring-boot-devtools'
    implementation 'mysql:mysql-connector-java:8.0.28'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation 'com.h2database:h2'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
}

tasks.named('test') {
    useJUnitPlatform()
}

src/test/resources/application-test.properties

spring.datasource.url=jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=sa

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=true

src/test/java///*/repository/UserRepositoryTest.java**

package ***.*******.*******.repository;

import static org.assertj.core.api.Assertions.assertThat;

import java.time.LocalDateTime;
import java.util.Optional;

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager;

import ***.*******.*******.model.User;

@DataJpaTest
public class UserRepositoryTest {
    @Autowired
    private TestEntityManager entityManager;

    @Autowired
    private UserRepository userRepository;
    User user;

    @BeforeEach
    void setUp() {
        user = new User("test", "test");
        user.setUserDateCreated(LocalDateTime.now());
        entityManager.persistAndFlush(user);
    }

    @AfterEach
    void tearDown() {
        user = null;
        userRepository.deleteAll();
    }

    @Test
    void testFindByUsername_Found() throws Exception {
        Optional<User> existingUser = userRepository.findByUsername("test");
        assertThat(existingUser.isPresent()).isTrue();
        assertThat(existingUser.get().getUserId()).isEqualTo(user.getUserId());
        assertThat(existingUser.get().getUsername()).isEqualTo(user.getUsername());
    }

    @Test
    void testFindByUsername_NotFound() throws Exception {
        Optional<User> existingUser = userRepository.findByUsername("test1");
        assertThat(existingUser.isPresent()).isFalse();
    }
}

src/main/java///*/BackendApplication.java**

package ***.*******.*******;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@SpringBootApplication()
public class BackendApplication implements WebMvcConfigurer {

    public static void main(String[] args) {
        SpringApplication.run(BackendApplication.class, args);
    }

}

src/main/java///*/repository/UserRepository.java**

package ***.*******.*******.repository;

import java.util.Optional;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import ***.*******.*******.model.User;

@Repository
public interface UserRepository extends JpaRepository<User, Integer> {
    Optional<User> findByUsername(String username);
}

src/main/resources/application.properties

spring.application.name=backend

# Server port
server.port=8080

# Datasource connection
spring.datasource.platform=mysql
spring.datasource.initialization-mode=always
spring.jpa.properties.hibernate.dialect.storage_engine=innodb

# Hibernate
spring.jpa.hibernate.ddl-auto=update
spring.jpa.hibernate.show-sql=true

# Logging
logging.level.org.springframework=ERROR
logging.level.com.numericaideas=DEBUG
logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE

test result

java.lang.IllegalStateException: Failed to load ApplicationContext for [MergedContextConfiguration@4487c0c2 testClass = com.crawler.backend.repository.UserRepositoryTest, locations = [], classes = [com.crawler.backend.BackendApplication], contextInitializerClasses = [], activeProfiles = [], propertySourceDescriptors = [], propertySourceProperties = ["org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTestContextBootstrapper=true"], contextCustomizers = [org.springframework.boot.test.autoconfigure.OverrideAutoConfigurationContextCustomizerFactory$DisableAutoConfigurationContextCustomizer@209da20d, org.springframework.boot.test.autoconfigure.actuate.observability.ObservabilityContextCustomizerFactory$DisableObservabilityContextCustomizer@1f, org.springframework.boot.test.autoconfigure.filter.TypeExcludeFiltersContextCustomizer@34be3d80, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@dbbec68d, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizer@59505b48, [ImportsContextCustomizer@126f1ba8 key = [org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration, org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration, org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManagerAutoConfiguration, org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration, org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration, org.springframework.boot.autoconfigure.sql.init.SqlInitializationAutoConfiguration, org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration, org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration, org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration, org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration, org.springframework.boot.autoconfigure.jdbc.JdbcClientAutoConfiguration, org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration, org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration]], org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@248e319b, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@3e8c3cb, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.reactor.netty.DisableReactorResourceFactoryGlobalResourcesContextCustomizerFactory$DisableReactorResourceFactoryGlobalResourcesContextCustomizerCustomizer@4b29d1d2, org.springframework.boot.test.context.SpringBootTestAnnotation@14ad81ff], contextLoader = org.springframework.boot.test.context.SpringBootContextLoader, parent = null]
 at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:180)
 at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:130)
 at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:142)
 at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:98)
 at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:260)
 at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:163)
 at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
 at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
 at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
 at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
 at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
 at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:310)
 at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
 at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
 at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)
 at java.base/java.util.Optional.orElseGet(Optional.java:364)
 at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
 at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Failed to initialize dependency 'dataSourceScriptDatabaseInitializer' of LoadTimeWeaverAware bean 'entityManagerFactory': Error creating bean with name 'dataSourceScriptDatabaseInitializer' defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourceScriptDatabaseInitializer' parameter 0: Error creating bean with name 'dataSource': Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:326)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:205)
 at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:954)
 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:625)
 at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754)
 at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:456)
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:335)
 at org.springframework.boot.test.context.SpringBootContextLoader.lambda$loadContext$3(SpringBootContextLoader.java:137)
 at org.springframework.util.function.ThrowingSupplier.get(ThrowingSupplier.java:58)
 at org.springframework.util.function.ThrowingSupplier.get(ThrowingSupplier.java:46)
 at org.springframework.boot.SpringApplication.withHook(SpringApplication.java:1463)
 at org.springframework.boot.test.context.SpringBootContextLoader$ContextLoaderHook.run(SpringBootContextLoader.java:553)
 at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:137)
 at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:108)
 at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:225)
 at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:152)
 ... 17 more
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'dataSourceScriptDatabaseInitializer' defined in class path resource [org/springframework/boot/autoconfigure/sql/init/DataSourceInitializationConfiguration.class]: Unsatisfied dependency expressed through method 'dataSourceScriptDatabaseInitializer' parameter 0: Error creating bean with name 'dataSource': Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
 at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:795)
 at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:542)

 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1355)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1185)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:522)
 at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:337)
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:335)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:313)
 ... 32 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource': Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1806)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:600)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:522)
 at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:337)
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:335)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
 at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:254)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1443)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1353)
 at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:904)
 at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:782)
 ... 42 more
Caused by: java.lang.IllegalStateException: Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
 at org.springframework.util.Assert.state(Assert.java:76)
 at org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration$EmbeddedDataSourceFactory.getEmbeddedDatabase(TestDatabaseAutoConfiguration.java:188)
 at org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration$EmbeddedDataSourceFactoryBean.afterPropertiesSet(TestDatabaseAutoConfiguration.java:153)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1853)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1802)
 ... 53 more

PS. I am using Docker in this development.