I recently got this error in Camel during unit testing:

Caused by: java.lang.IllegalArgumentException: bean, ref or beanType must be provided

In case others come across the same issue, I thought I’d do a quick write-up on what the solution in my specific scenario was. Consider these production code extracts:

// File: InputDataValidator.java
@Component
public class InputDataValidator {
    
    public Processor validate() {
        return exchange -> {
            // Validate data
            exchange.getIn();
        };
    }

    public Processor validateSomethingElse() {
        return exchange -> {
            // Validate data
            exchange.getIn();
        };
    }
}

// File: MyRoute.java

@Component
public class MyRoute extends RouteBuilder {
    
    private InputDataValidator inputDataValidator;

    @Autowired
    public MyRoute(InputDataValidator inputDataValidator) {
        this.inputDataValidator = inputDataValidator;
    }

    @Override
    public void configure() {
        from("direct:input")
            .bean(this.inputDataValidator.validate());  // This did not work
    }
}

The unit test:

// File: MyRouteTest.java

@CamelSpringBootTest
@SpringBootTest(classes = {MyApplication.class})
@UseAdviceWith
@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
public class MyRouteTest {

    @MockBean
    private InputDataValidator mockedValidator;

    @Autowired
    private CamelContext context;

    @Test
    public void test() throws Exception {

        String errorMessage = "ERROR";
        doThrow(new ValidationException(errorMessage)).when(mockedValidator).validate();

        context.start();

        FluentProducerTemplate fluentProducerTemplate;

        fluentProducerTemplate = context.createFluentProducerTemplate().to(ROUTE_DIRECT_VALIDERE_OPPSLAG);
        Message result = fluentProducerTemplate.withHeader("key", "value").request(Message.class);

        assertEquals(400, result.getHeader("CamelHttpResponseCode"));
        assertEquals(Feil.class, result.getBody().getClass());
        assertEquals("400", (result.getBody(Feil.class).getKode()));
        assertEquals(errorMessage, (result.getBody(Feil.class).getMelding()));
    }
}

When running the unit test, I got the error referenced in the title:

java.lang.IllegalArgumentException: bean, ref or beanType must be provided

To get the test to work, just a very small adjustment to the production code was required:

from("direct:input")
     // .bean(this.inputDataValidator.validate());  // This did not work
     .bean(this.inputDataValidator, "validate");  // This worked

I’m running Camel 3.18.1.