Different datasources in TEST and DEVELOPMENT environment
environments {
    development {
    grails.naming.entries = [
        "jdbc/AS400DS": [
               ...
        ]
    ]
    }
    test {
    grails.naming.entries = [
        "java:comp/env/jdbc/AS400DS": [
               ...
        ]
    ]
    }
}

dataSource {
    pooled = false
}

hibernate {
    cache.use_second_level_cache=true
    cache.use_query_cache=true
    cache.provider_class='org.hibernate.cache.EhCacheProvider'
}

// environment specific settings
environments {
    development {
        dataSource {
            dbCreate = "validate" // one of 'create', 'create-drop','update'
            jndiName = "java:comp/env/jdbc/databaseName"
        }
    }
    test {
        dataSource {
            driverClassName = "com.mysql.jdbc.Driver"
            username = "username"
            password = "password"
            dbCreate = "validate" // one of 'create', 'create-drop','update'
            url = "jdbc:mysql://127.0.0.1:3306/databaseName"
    }
}