docs: Link to test.md from initial tutorial (#2257)

* docs: Link to test.md from initial tutorial

* Update faststream.md

Author: sobolevn

docs/docs/en/faststream.md

@@ -220,7 +220,7 @@ to define messages using a declarative syntax, making it easy to specify the fie
 
 ## Testing the service
 
-The service can be tested using the `TestBroker` context managers, which, by default, puts the Broker into "testing mode".
+The service can be [tested](./getting-started/subscription/test.md){.internal-link} using the `TestBroker` context managers, which, by default, puts the Broker into "testing mode".
 
 The Tester will redirect your `subscriber` and `publisher` decorated functions to the InMemory brokers, allowing you to quickly test your app without the need for a running broker and all its dependencies.