### Question:
FileStreamSourceConnector extends SourceConnector { @Override public void start(Map<String, String> props) { filename = props.get(FILE_CONFIG); topic = props.get(TOPIC_CONFIG); if (topic == null || topic.isEmpty()) throw new ConnectException("FileStreamSourceConnector configuration must include 'topic' setting"); if (topic.contains(",")) throw new ConnectException("FileStreamSourceConnector should only have a single topic when used as a source."); }  @Override String version(); @Override void start(Map<String, String> props); @Override Class<? extends Task> taskClass(); @Override List<Map<String, String>> taskConfigs(int maxTasks); @Override void stop(); @Override ConfigDef config(); static final String TOPIC_CONFIG; static final String FILE_CONFIG; }### Answer:
@Test(expected = ConnectException.class) public void testMultipleSourcesInvalid() { sourceProperties.put(FileStreamSourceConnector.TOPIC_CONFIG, MULTIPLE_TOPICS); connector.start(sourceProperties); }