Either its a bug in Weld or its packaging issue of org.jboss.jsr299.tck.tests.extensions.container.event.ContainerEventTest.ear appears to be incorrect.

Here is the content of this ear file of a jsr299 tck test:

org.jboss.jsr299.tck.tests.extensions.container.event.ContainerEventTest.ear
-META-INF/services/javax.enterprise.inject.spi.Extension ==> with entries for Observer classes

• org.jboss.jsr299.tck.tests.extensions.container.event.ContainerEventTest.jar
• ...

The META-INF/services//javax.enterprise.inject.spi.Extension entries are defined as:

org.jboss.jsr299.tck.tests.extensions.container.event.ProcessBeanObserver
org.jboss.jsr299.tck.tests.extensions.container.event.ProcessInjectionTargetObserver
org.jboss.jsr299.tck.tests.extensions.container.event.ProcessAnnotatedTypeObserver

Weld does not scan org.jboss.jsr299.tck.tests.extensions.container.event.ContainerEventTest.jar for presence of Extension in the included jar file. If this behavior is not what jsr299 spec desires then a tleast the packaging should be such that the META-INF/services Extension classes are moved inside the jar file. JSR 299 is not clear on this but It seems that it should be expected to scan all the jars files included in the EAR file for presence of Extension.