I get:

java.lang.NullPointerException
at org.jboss.arquillian.impl.DeployableTestBuilder.build(DeployableTestBuilder.java:82)
at org.jboss.arquillian.impl.DeployableTestBuilder.build(DeployableTestBuilder.java:71)
at org.jboss.arquillian.junit.Arquillian.<init>(Arquillian.java:68)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

Any component that uses a SPI implementation should guard against null values - if there is a non-null requirement of course - and throw an IllegalArgumentException with a descriptive error message.