Update test binder documentation

Fix #867

* Switch to Spring Boot 1.4 and later configuration
* Add artifact reference
* Remove @DirtiesContext and autowired BinderFactory field

spring-cloud-stream-core-docs/src/main/asciidoc/spring-cloud-stream-overview.adoc

@@ -1759,8 +1759,22 @@ While a scenario which using multiple instances for partitioned data processing
 == Testing
 
 Spring Cloud Stream provides support for testing your microservice applications without connecting to a messaging system.
-You can do that by using the `TestSupportBinder`.
-This is useful especially for unit testing your microservices.
+You can do that by using the `TestSupportBinder` provided by the `spring-cloud-stream-test-support` library, which can be added as a test dependency to the application:
+
+[source,xml]
+----
+   <dependency>
+       <groupId>org.springframework.cloud</groupId>
+       <artifactId>spring-cloud-stream-test-support</artifactId>
+       <scope>test</scope>
+   </dependency>
+----
+
+[NOTE]
+====
+The `TestSupportBinder` uses the Spring Boot autoconfiguration mechanism to supersede the other binders found on the classpath.
+Therefore, when adding a binder as a dependency, make sure that the `test` scope is being used.
+====
 
 The `TestSupportBinder` allows users to interact with the bound channels and inspect what messages are sent and received by the application
 
@@ -1772,18 +1786,13 @@ The following example shows how to test both input and output channels on a proc
 
 [source,java]
 ----
-@RunWith(SpringJUnit4ClassRunner.class)
-@SpringApplicationConfiguration(classes = ExampleTest.MyProcessor.class)
-@IntegrationTest({"server.port=-1"})
-@DirtiesContext
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment= SpringBootTest.WebEnvironment.RANDOM_PORT)
 public class ExampleTest {
 
   @Autowired
   private Processor processor;
 
-  @Autowired
-  private BinderFactory<MessageChannel> binderFactory;
-
   @Autowired
   private MessageCollector messageCollector;