@DataJpaTest updating actual data in case of MySQL but working fine with H2

I am learning @DataJpaTest, my test case is as below

import com.demo.mockito.entity.StudentEntity;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
@DataJpaTest
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
class StudentRepositoryTest {
    @Autowired
    private StudentRepository studentRepository;
    @Test
    public void findAll() {
        StudentEntity student1 = new StudentEntity("shrikant", new Date());
        studentRepository.save(student1);
        List<StudentEntity> entityList = studentRepository.findAll();
        assertEquals(1, entityList.size());
    }
}

it's giving me the error

expected: <1> but was: <33>
Expected :1
Actual   :33
<Click to see difference>

because right now there are 33 records in DB, and with every save test case, it increases.

src/main/test/application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/student_db?jdbcCompliantTruncation=false&sessionVariables=sql_mode='NO_ENGINE_SUBSTITUTION'&useSSL=false&useServerPrepStmts=false&rewriteBatchedStatements=true&useUnicode=true&characterEncoding=utf8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
spring.jpa.generate-ddl=true
spring.jpa.database.schema=student_db
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

build.gradle

plugins {
    id 'java'
    id 'org.springframework.boot' version '2.2.6.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
}
group 'com.demo.mockito'
version '1.0-SNAPSHOT'
repositories {
    mavenCentral()
}
dependencies {
    compile 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    testRuntime('org.junit.jupiter:junit-jupiter-engine:5.2.0')
    runtime 'mysql:mysql-connector-java'
    testImplementation('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
}
test {
    useJUnitPlatform()
}

if i use h2 instead, it gives correct result beucase every time it recreates a new instance with no data.

is this intended behavior? or am I doing something wrong, is h2 standard in case of database testing. but I don't want to configure another database in my application when my intention is to test MySQL only.