Using H2 database for integration testing in Grails - grails

Question

My understanding is by default Grails using the H2 embedded database for testing.
My Datasource.groovy configures a local Postgres database as a root datasoure
dataSource {
driverClassName = "org.postgresql.Driver"
dialect = org.hibernate.dialect.PostgreSQLDialect
url = ...
pooled = true
...
But I don't want this used in integration testing. I would prefer to use the H2 embedded option. So how do I override this for integration test environment and make it use embedded H2 database?
Thanks

Answer 1

Place the baseline configuration in the dataSource block and override it with an environment block as explained in section 4.2 Environments of the Grails documentation.
dataSource {
pooled = true
driverClassName = "org.h2.Driver"
username = "sa"
password = ""
}
environments {
development {
dataSource {
dbCreate = "create-drop"
url = "jdbc:h2:mem:devDb:MVCC=TRUE;LOCK_TIMEOUT=10000"
}
}
test {
dataSource {
dbCreate = "update"
url = "jdbc:h2:mem:testDb:MVCC=TRUE;LOCK_TIMEOUT=10000"
}
}
production {
dataSource {
driverClassName = "org.postgresql.Driver"
dialect = org.hibernate.dialect.PostgreSQLDialect
dbCreate = ...
url = ...
}
}
}

Answer 2

I have the same question, but until now i didn't find an answer. Perhaps setting the field dialect inside Datasource.groovy like this:
test {
dataSource {
dbCreate = "update"
dialect='org.hibernate.dialect.H2DialectPatch'
url = "jdbc:h2:mem:testDb;MVCC=TRUE;LOCK_TIMEOUT=10000;DB_CLOSE_ON_EXIT=FALSE"
}
}