This is an example:

org.jboss.arquillian.impl.event.FiredEventException: java.lang.IllegalStateException: Error launching test com.acme.cache.NamedCacheTest public void com.acme.cache.NamedCacheTest.testThis()
at org.jboss.arquillian.impl.event.MapEventManager.fire(MapEventManager.java:68)
at org.jboss.arquillian.impl.context.AbstractEventContext.fire(AbstractEventContext.java:115)
at org.jboss.arquillian.impl.EventTestRunnerAdaptor.test(EventTestRunnerAdaptor.java:157)
at org.jboss.arquillian.junit.Arquillian$6.evaluate(Arquillian.java:244)
at org.jboss.arquillian.junit.Arquillian$4.evaluate(Arquillian.java:207)
at org.jboss.arquillian.junit.Arquillian$5$1.evaluate(Arquillian.java:225)
at org.jboss.arquillian.junit.Arquillian$MultiStatementExecutor.execute(Arquillian.java:297)
at org.jboss.arquillian.junit.Arquillian$5.evaluate(Arquillian.java:221)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.jboss.arquillian.junit.Arquillian$2.evaluate(Arquillian.java:163)
at org.jboss.arquillian.junit.Arquillian$3$1.evaluate(Arquillian.java:186)
at org.jboss.arquillian.junit.Arquillian$MultiStatementExecutor.execute(Arquillian.java:297)
at org.jboss.arquillian.junit.Arquillian$3.evaluate(Arquillian.java:182)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.jboss.arquillian.junit.Arquillian.run(Arquillian.java:127)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.IllegalStateException: Error launching test com.acme.cache.NamedCacheTest public void com.acme.cache.NamedCacheTest.testThis()
at org.jboss.arquillian.protocol.servlet_3.ServletMethodExecutor.invoke(ServletMethodExecutor.java:61)
at org.jboss.arquillian.impl.handler.ContainerTestExecuter.callback(ContainerTestExecuter.java:50)
at org.jboss.arquillian.impl.handler.ContainerTestExecuter.callback(ContainerTestExecuter.java:40)
at org.jboss.arquillian.impl.event.MapEventManager.fire(MapEventManager.java:63)
... 26 more
Caused by: java.lang.ClassNotFoundException: org.jboss.weld.exceptions.IllegalArgumentException
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:603)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1574)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1495)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1731)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at org.jboss.arquillian.protocol.servlet_3.ServletMethodExecutor.execute(ServletMethodExecutor.java:88)
at org.jboss.arquillian.protocol.servlet_3.ServletMethodExecutor.invoke(ServletMethodExecutor.java:57)
... 29 more

As you can see here, "org.jboss.weld.exceptions.IllegalArgumentException" isn't in the classpath of the client.

It shouldn't be necessary to include the Weld jarfiles in my build path to receive this exception. Instead, Arquillian could convert these exceptions into more generic ones. (On the server, logging something useful would be appreciated.)