@Test
    public void testProcessNotFound() throws Exception {
        ExternalCommandWorker worker =
            new ExternalCommandWorkerBuilder("notFoundTask").
                command("/dev/null/non/existent/script/path").build();
        KafkaFutureImpl<String> doneFuture = new KafkaFutureImpl<>();
        worker.start(null, new AgentWorkerStatusTracker(), doneFuture);
        String errorString = doneFuture.get();
        assertTrue(errorString.startsWith("Unable to start process"));
        worker.stop(null);
    }
Test attempting to run an executable which doesn't exist.
We use a path which starts with /dev/null, since that should never be a
directory in UNIX.
trogdor/src/test/java/org/apache/kafka/trogdor/workload/ExternalCommandWorkerTest.java