I've run Arq mostly to just start an AS7 and did not deploy any test classes to it (it is complaining). Later for each test method it seems to throw a NPE:

java.lang.NullPointerException
at org.jboss.arquillian.container.impl.client.container.ContainerDeployController.forEachDeployedDeployment(ContainerDeployController.java:228)
at org.jboss.arquillian.container.impl.client.container.ContainerDeployController.undeployManaged(ContainerDeployController.java:99)
at org.jboss.arquillian.core.impl.ObserverImpl.invoke(ObserverImpl.java:90)
at org.jboss.arquillian.core.impl.EventContextImpl.invokeObservers(EventContextImpl.java:99)
at org.jboss.arquillian.core.impl.EventContextImpl.proceed(EventContextImpl.java:81)
at org.jboss.arquillian.core.impl.ManagerImpl.fire(ManagerImpl.java:134)
at org.jboss.arquillian.core.impl.ManagerImpl.fire(ManagerImpl.java:114)
at org.jboss.arquillian.core.impl.EventImpl.fire(EventImpl.java:67)
at org.jboss.arquillian.container.test.impl.client.ContainerEventController.execute(ContainerEventController.java:102)
at org.jboss.arquillian.core.impl.ObserverImpl.invoke(ObserverImpl.java:90)
at org.jboss.arquillian.core.impl.EventContextImpl.invokeObservers(EventContextImpl.java:99)
at org.jboss.arquillian.core.impl.EventContextImpl.proceed(EventContextImpl.java:81)
at org.jboss.arquillian.test.impl.TestContextHandler.createClassContext(TestContextHandler.java:68)
at org.jboss.arquillian.core.impl.ObserverImpl.invoke(ObserverImpl.java:90)
at org.jboss.arquillian.core.impl.EventContextImpl.proceed(EventContextImpl.java:88)
at org.jboss.arquillian.test.impl.TestContextHandler.createSuiteContext(TestContextHandler.java:54)
at org.jboss.arquillian.core.impl.ObserverImpl.invoke(ObserverImpl.java:90)
at org.jboss.arquillian.core.impl.EventContextImpl.proceed(EventContextImpl.java:88)
at org.jboss.arquillian.core.impl.ManagerImpl.fire(ManagerImpl.java:134)
at org.jboss.arquillian.core.impl.ManagerImpl.fire(ManagerImpl.java:114)
at org.jboss.arquillian.test.impl.EventTestRunnerAdaptor.afterClass(EventTestRunnerAdaptor.java:87)
at org.jboss.arquillian.testng.Arquillian.arquillianAfterClass(Arquillian.java:82)
at org.apache.maven.surefire.testng.TestNGExecutor.run(TestNGExecutor.java:61)
at org.apache.maven.surefire.testng.TestNGDirectoryTestSuite.execute(TestNGDirectoryTestSuite.java:144)
at org.apache.maven.surefire.Surefire.run(Surefire.java:169)

While it is a result of a previous error, it should not NPE.