spring-cloud-stream-test-binder-issue-demo

This is a demo of the problem where the OutputDestination cannot be Dependency Injected (DI) when using the Test Binder, StreamBridge, and OutputDestination without registering a message handler.

Environment

• Java 17
• Spring Boot 3.1.1
• Spring Cloud 2022.0.3
• Spring Cloud Stream 4.0.3

Demo

source code

$ cd issue-demo
$ mvn clean test

Log excerpt

[ERROR] Errors:
[ERROR]   AppTest.test » UnsatisfiedDependency Error creating bean with name 'com.example.AppTest': Unsatisfied dependency expressed through field 'outputDestination': No qualifying bean of type 'org.springframework.cloud.stream.binder.test.OutputDestination' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

Workaround 1

source code

$ cd workaround-1
$ mvn clean test

Use @Import(TestChannelBinderConfiguration.class) (the previous method).

Workaround 2

source code

$ cd workaround-2
$ mvn clean test

Use @Lazy to delay DI. This method requires calling StreamBridge#send before using the OutputDestination variable.