@Test
    public void testBlockInConnectorConfig() throws Exception {
        log.info("Starting test testBlockInConnectorConfig");
        assertRequestTimesOut(
                "create connector that blocks while getting config",
                () -> createConnectorWithBlock(ConfigBlockingConnector.class, CONNECTOR_CONFIG),
                "The worker is currently retrieving the configuration definition from the connector"
        );
        // Will NOT assert that connector has failed, since the request should fail before it's even created

        // Connector should already be blocked so this should return immediately, but check just to
        // make sure that it actually did block
        Block.waitForBlock();

        createNormalConnector();
        verifyNormalConnector();
    }
Tests situations during which certain connector operations, such as start, validation,
configuration and others, take longer than expected.
connect/runtime/src/test/java/org/apache/kafka/connect/integration/BlockingConnectorTest.java