Embedded GlassFish inside Grails - grails

Question

I'm using Grails 2.2.3 together with the Grails GlassFish plugin: http://grails.org/plugin/glassfish
So far, everything works as expected (run-app), except integration testing that in my understanding should startup/tear down a GlassFish instance as well.
When I try to run integration tests, I get a weird exception (see below).
It seems like if I run test-app :integration, the GlassFish instance is not started by Grails.
Any ideas?
Here's the exception:
Testing started at 18:58 ...
| Loading Grails 2.2.3
| Configuring classpath
| Error SLF4J: Class path contains multiple SLF4J bindings.
| Error SLF4J: Found binding in [jar:file:/Users/markus/.grails/ivy-cache/org.slf4j/slf4j-log4j12/jars/slf4j-log4j12-1.6.6.jar!/org/slf4j/impl/StaticLoggerBinder.class]
| Error SLF4J: Found binding in [jar:file:/Users/markus/.grails/ivy-cache/org.glassfish.main.extras/glassfish-embedded-all/jars/glassfish-embedded-all-3.1.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]
| Error SLF4J: Found binding in [jar:file:/Users/markus/.grails/ivy-cache/org.grails/grails-plugin-log4j/jars/grails-plugin-log4j-2.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
| Error SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
| Error SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
| Configuring classpath.
| Environment set to test
| Environment set to test.
| Environment set to test..
| Environment set to test...
| Environment set to test....
| Environment set to test.....
| Packaging Grails application
| Packaging Grails application.
| Packaging Grails application..
| Packaging Grails application...
| Packaging Grails application....
| Packaging Grails application.....
26.06.2013 18:58:44 com.sun.enterprise.v3.server.CommonClassLoaderServiceImpl findDerbyClient
INFO: Cannot find javadb client jar file, derby jdbc driver will not be available by default.
| Packaging Grails application
| Packaging Grails application.
| Packaging Grails application..
| Packaging Grails application...
| Packaging Grails application...
| Packaging Grails application....
| Packaging Grails application.....
| Error org.omg.CORBA.COMM_FAILURE: FEIN: IOP00410001: Connection failure: socketType: IIOP_CLEAR_TEXT; hostname: localhost; port: 3700 vmcid: OMG minor code: 1 completed: No
| Error at sun.reflect.GeneratedConstructorAccessor51.newInstance(Unknown Source)
| Error at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
| Error at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
| Error at com.sun.corba.ee.spi.orbutil.logex.corba.CorbaExtension.makeException(CorbaExtension.java:248)
| Error at com.sun.corba.ee.spi.orbutil.logex.corba.CorbaExtension.makeException(CorbaExtension.java:95)
| Error at com.sun.corba.ee.spi.orbutil.logex.WrapperGenerator.handleFullLogging(WrapperGenerator.java:387)
| Error at com.sun.corba.ee.spi.orbutil.logex.WrapperGenerator.access$400(WrapperGenerator.java:107)
| Error at com.sun.corba.ee.spi.orbutil.logex.WrapperGenerator$2.invoke(WrapperGenerator.java:511)
| Error at com.sun.corba.ee.spi.orbutil.proxy.CompositeInvocationHandlerImpl.invoke(CompositeInvocationHandlerImpl.java:99)
| Error at com.sun.proxy.$Proxy32.connectFailure(Unknown Source)