Make hibernate point to the same DB connection as DBUnit - mysql

Question

I am using hiberante jpa to connect to a mysql database.
My persistence-unit in my persistence.xml looks like this:
<persistence-unit name="inventoryManager">
<!--some settings-->
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/inventory?useSSL=false&useUnicode=true&useJDBCCompliantTimezoneS‌​hift=true&useLegacyDatetimeCode=false&serverTimezone=UTC"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="1234"/>
<!--Hibernate properties-->
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
<property name="hibernate.show_sql" value="false"/>
<property name="hibernate.format_sql" value="false"/>
<property name="hibernate.hbm2ddl.auto" value="validate"/>
</properties>
</persistence-unit>
My DAO´s are using this connection to execute all the operations with the database.
I am also using DBUnit for the tests, but I am using an in-memory database(hsql). and its configuration in my test case constructor looks like this:
System.setProperty( PropertiesBasedJdbcDatabaseTester.DBUNIT_DRIVER_CLASS, "org.hsqldb.jdbcDriver" );
System.setProperty( PropertiesBasedJdbcDatabaseTester.DBUNIT_CONNECTION_URL, "jdbc:hsqldb:mem:db" );
System.setProperty( PropertiesBasedJdbcDatabaseTester.DBUNIT_USERNAME, "sa" );
System.setProperty( PropertiesBasedJdbcDatabaseTester.DBUNIT_PASSWORD, "" );
System.setProperty( PropertiesBasedJdbcDatabaseTester.DBUNIT_SCHEMA, "db" );
So when I run a test that calls one DAO. The DAO instantiates an entityManager which points to the mysql connetion specified in the persistence.xml
The question is: How do I make the entityManager inside my DAO to point to my in-memory database?
Thanks in advance!

Answer 1

As you are not using Spring you can try a Maven based solution. This involves creating a separate persistence.xml under src/test/resources/META-INF with the relevant properties.
When running your tests this persistence.xml should take precedence over the one in src/main/resources.

Answer 2

You can do something like below:
1.Create a datasource bean pointing to In Memory DB something like below
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="org.hsqldb.jdbc.JDBCDriver" />
<property name="jdbcUrl"
value="jdbc:hsqldb:file:/data/data.db" />
</bean>
2.Define a EntityManagerFactory which will refer to this DataSource.
3.Add both these beans in a testConfig.xml
4.Run with JUnit
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations ={ "testconfig.xml" })