How to test MessageChannel in Spring Integrtion? - spring

Question

I'm trying to know if the message passed through specific channel for test or i'd like to get the message from specific channel
So my flow is: controller -> gateway -> ServiceActivator
private final Gateway gateway;
public ResponseEntity<Map<String,String>> submit(String applicationId, ApplicationDto applicationDto) {
applicationDto.setApplicationId(applicationId);
gateway.submitApplication(applicationDto);
return ResponseEntity.ok(Map.of(MESSAGE, "Accepted submit"));
}
the gateway
#Gateway(requestChannel = "submitApplicationChannel", replyChannel = "replySubmitApplicationChannel")
WorkflowPayload submitApplication(ApplicationDto applicationDto);
pipeline
#Bean
MessageChannel submitApplicationChannel() {
return new DirectChannel();
}
So my test is sending a request to start the flow
#Test
#DisplayName("Application Submission")
void submissionTest() throws Exception {
mockMvc.perform(MockMvcRequestBuilders
.post("/api/v1/applications/contract-validation/" + APPLICATION_ID)
.contentType(MediaType.APPLICATION_JSON)
.content(objectMapper.writeValueAsString(payload)))
.andExpect(status().isAccepted())
.andReturn();
//Check HERE if the message passed through the channel
}
Can you give me a hand??

Answer 1

In your test, add a ChannelInterceptor to the submitApplicationChannel before calling the gateway.
public interface ChannelInterceptor {
/**
* Invoked before the Message is actually sent to the channel.
* This allows for modification of the Message if necessary.
* If this method returns {#code null} then the actual
* send invocation will not occur.
*/
#Nullable
default Message<?> preSend(Message<?> message, MessageChannel channel) {
return message;
}
/**
* Invoked immediately after the send invocation. The boolean
* value argument represents the return value of that invocation.
*/
default void postSend(Message<?> message, MessageChannel channel, boolean sent) {
}
/**
* Invoked after the completion of a send regardless of any exception that
* have been raised thus allowing for proper resource cleanup.
* <p>Note that this will be invoked only if {#link #preSend} successfully
* completed and returned a Message, i.e. it did not return {#code null}.
* #since 4.1
*/
default void afterSendCompletion(
Message<?> message, MessageChannel channel, boolean sent, #Nullable Exception ex) {
}
/**
* Invoked as soon as receive is called and before a Message is
* actually retrieved. If the return value is 'false', then no
* Message will be retrieved. This only applies to PollableChannels.
*/
default boolean preReceive(MessageChannel channel) {
return true;
}
/**
* Invoked immediately after a Message has been retrieved but before
* it is returned to the caller. The Message may be modified if
* necessary; {#code null} aborts further interceptor invocations.
* This only applies to PollableChannels.
*/
#Nullable
default Message<?> postReceive(Message<?> message, MessageChannel channel) {
return message;
}
/**
* Invoked after the completion of a receive regardless of any exception that
* have been raised thus allowing for proper resource cleanup.
* <p>Note that this will be invoked only if {#link #preReceive} successfully
* completed and returned {#code true}.
* #since 4.1
*/
default void afterReceiveCompletion(#Nullable Message<?> message, MessageChannel channel,
#Nullable Exception ex) {
}
}