How do you test Camel routes using camel-test and the MockEndpoint?

The Camel test kit allows you to stub real endpoints with in-memory MockEndpoints and set expectations on the messages they receive. The test extends CamelTestSupport, which boots a full in-memory CamelContext. MockEndpoints intercept to(uri) calls when you advise the route to replace real endpoints.

public class OrderRouteTest extends CamelTestSupport {

    @Override
    protected RoutesSupplier createRouteBuilder() {
        return new OrderRoute();   // the route under test
    }

    @Test
    public void testOrderRouted() throws Exception {
        MockEndpoint mock = getMockEndpoint("mock:jms:queue:processed");
        mock.expectedMessageCount(1);
        mock.expectedHeaderReceived("orderId", "ORD-001");

        // Replace real endpoint with mock in route definition:
        context.getRouteController().startRoute("order-route");
        template.sendBodyAndHeader("direct:orders", "{amount:99}",
                                  "orderId", "ORD-001");

        mock.assertIsSatisfied();
    }
}

Use AdviceWith.adviceWith() to intercept and mock specific endpoints inside a route without modifying the route class. The ProducerTemplate (template field) lets you inject test messages into any direct: or other endpoint. MockEndpoint supports assertions on message count, body content, header values, received order, and no-messages-within-time. For Spring Boot integration tests, use @SpringBootTest with CamelSpringBootRunner.