Build Error in Tests

ests run: 2, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.031 sec <<< FAILURE! - in org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OFOverlayRendererTest
applyConfigTest(org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OFOverlayRendererTest)  Time elapsed: 0.016 sec  <<< ERROR!
java.lang.reflect.InvocationTargetException: null
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.node.SwitchManager$2.apply(SwitchManager.java:122)
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.node.SwitchManager$2.apply(SwitchManager.java:118)
	at com.google.common.collect.Iterators$7.computeNext(Iterators.java:652)
	at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143)
	at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
	at com.google.common.collect.TransformedIterator.hasNext(TransformedIterator.java:43)
	at com.google.common.collect.ImmutableCollection$Builder.addAll(ImmutableCollection.java:300)
	at com.google.common.collect.ImmutableList$Builder.addAll(ImmutableList.java:691)
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:275)
	at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:226)
	at com.google.common.collect.FluentIterable.toList(FluentIterable.java:373)
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.node.SwitchManager.getReadySwitches(SwitchManager.java:117)
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.PolicyManager.removeUnusedTables(PolicyManager.java:220)
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.PolicyManager.changeOpenFlowTableOffset(PolicyManager.java:201)
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OFOverlayRenderer.applyConfig(OFOverlayRenderer.java:180)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OFOverlayRendererTest.applyConfigTest(OFOverlayRendererTest.java:87)