Tests containing persistence units fail to deploy due to NoClassDefFoundError

Tests affected:
org.jboss.test.jpa.test.WebClassesEARJPAUnitTestCase
org.jboss.test.jpa.test.WebClassesJPAUnitTestCase
org.jboss.test.jpa.test.WebLibsEARJPAUnitTestCase
org.jboss.test.jpa.test.WebLibsJPAUnitTestCase
org.jboss.test.deployers.seam.test.SeamDvdExampleUnitTestCase(profileservice)
org.jboss.test.deployers.seam.test.SeamJPAExampleUnitTestCase(profileservice)
org.jboss.test.hibernate.test.HibernateIntgUnitTestCase
org.jboss.test.hibernate.test.TimersUnitTestCase

15:00:32,180 ERROR [AbstractKernelController] Error installing to Start: name=persistence.unit:unitName=test-jpa-webclasses.ear/test-jpa-webclasses.war#test state=Create
java.lang.NoClassDefFoundError: net/sf/cglib/proxy/CallbackFilter
at org.hibernate.bytecode.cglib.BytecodeProviderImpl.getProxyFactoryFactory(BytecodeProviderImpl.java:33)
at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactoryInternal(PojoEntityTuplizer.java:182)
at org.hibernate.tuple.entity.PojoEntityTuplizer.buildProxyFactory(PojoEntityTuplizer.java:160)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.<init>(AbstractEntityTuplizer.java:135)
at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:55)
at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.<init>(EntityEntityModeToTuplizerMapping.java:56)
at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:302)
at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:434)
at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:109)
at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:55)
at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:226)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1300)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:867)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:669)
at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:132)
at org.jboss.jpa.deployment.PersistenceUnitDeployment.start(PersistenceUnitDeployment.java:301)