====== Using H2 As DataSource For Testing ======
  - In build.gradle, add ''runtimeOnly 'com.h2database:h2'' in dependencies section
  - Open application.properties
  - Add lines<code>spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.h2.console.enabled=true</code> Note that we set console.enable to true so that we can access H2 by web browser
  - To access the H2 database, go to http://localhost:8080/h2-console/ for default setting


For maven: 
<code>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <scope>runtime</scope>
</dependency>
</code>