title: Spring Cloud Stream 3.0.7 testing logic
body: <p>As someone new to Spring but with a streams processing background, I'm pretty confused about how I should be testing processors written in Spring Cloud Stream. The testing <a href="https://cloud.spring.io/spring-cloud-static/spring-cloud-stream/2.2.0.RELEASE/spring-cloud-stream.html#_testing" rel="nofollow noreferrer">docs</a> (written for 2.2.0 but seemingly the most recent, so still valid for 3.0.7 I guess?) indicate that a processor should be autowired into the test class via annotation, but there's no mention of where this 'Processor' bean comes from. I've tried to make it available via:</p>
  <pre><code>import org.springframework.cloud.stream.messaging.Processor;
  ...
  
  @Autowired
  private Processor processor;
  </code></pre>
  <p>but when running the tests, the exception is always the same:</p>
  <pre><code>Unsatisfied dependency expressed through field 'processor'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.cloud.stream.messaging.Processor' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
  </code></pre>
  <p>Am I even on the right path here? There seems to be lots of deprecated features in the past year so any pointers to more recent documentation would be appreciated.</p>