@Test
    public void testPrettyPrintException() {
        assertEquals("Null exception.", KafkaAdminClient.prettyPrintException(null));
        assertEquals("TimeoutException", KafkaAdminClient.prettyPrintException(new TimeoutException()));
        assertEquals("TimeoutException: The foobar timed out.",
                KafkaAdminClient.prettyPrintException(new TimeoutException("The foobar timed out.")));
    }
A unit test for KafkaAdminClient.

See AdminClientIntegrationTest for an integration test.
clients/src/test/java/org/apache/kafka/clients/admin/KafkaAdminClientTest.java