TEST_DIR=/tmp/test_dir
mkdir -p $TEST_DIR
head -c 1K </dev/urandom > ${TEST_DIR}/random.data
echo 'value' > ${TEST_DIR}/my.property

sh wildfly-14.0.0.Beta1-SNAPSHOT/bin/standalone.sh &
sh wildfly-14.0.0.Beta1-SNAPSHOT/bin/jboss-cli.sh -c "/subsystem=microprofile-config-smallrye/config-source=config:add(dir=${TEST_DIR})"

12:53:59,083 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 1) WFLYCTL0013: Operation ("add") failed - address: ([
    ("subsystem" => "microprofile-config-smallrye"),
    ("config-source" => "asd")
]): java.io.UncheckedIOException: java.nio.charset.MalformedInputException: Input length = 1
	at java.io.BufferedReader$1.hasNext(BufferedReader.java:574)
	at java.util.Iterator.forEachRemaining(Iterator.java:115)
	at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
	at io.smallrye.config.DirConfigSource.readContent(DirConfigSource.java:72)
	at io.smallrye.config.DirConfigSource.scan(DirConfigSource.java:60)
	at io.smallrye.config.DirConfigSource.<init>(DirConfigSource.java:46)
	at org.wildfly.extension.microprofile.config.smallrye.ConfigSourceDefinition$1.performRuntime(ConfigSourceDefinition.java:120)
...