org.wildfly.clustering.web.infinispan.CacheMutatorTestCase failing

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Test set: org.wildfly.clustering.web.infinispan.CacheMutatorTestCase
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Tests run: 2, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.054 sec <<< FAILURE!
isMutable(org.wildfly.clustering.web.infinispan.CacheMutatorTestCase) Time elapsed: 0.034 sec <<< ERROR!
java.lang.IllegalArgumentException
at java.util.Currency.getInstance(Currency.java:361)
at org.wildfly.clustering.web.infinispan.CacheMutatorTestCase.isMutable(CacheMutatorTestCase.java:71)
assertFalse(CacheMutator.isMutable(Currency.getInstance(Locale.getDefault())));

The default locale can be defined by different things. In my case default locale is 'en'.
Currency.getInstance does not like this Locale as this seems not to be linked to a country.

I think it's better to use a defined Locale here like Locale.GERMANY.