Reword

Author: javiereguiluz

mailer.rst

@@ -954,9 +954,10 @@ Development & Debugging
 Disabling Delivery
 ~~~~~~~~~~~~~~~~~~
 
-While developing (or testing), you may want to disable delivery of messages entirely.
-You can do this by forcing Mailer to use the ``NullTransport`` in only the ``dev``
-environment:
+While developing (or testing), you may want to disable delivery of messages
+entirely. You can do this by using ``null://null`` as the mailer DSN, either in
+your :ref:`.env configuration files <configuration-multiple-env-files>` or in
+the mailer configuration file (e.g. in the ``dev`` or ``test`` environments):
 
 .. configuration-block::
 
@@ -994,14 +995,6 @@ environment:
             ],
         ]);
 
-You can also disable delivering with an environment variable in your `.env.test` file
-(or you can create a `.env.test.local` file for example) :
-
-.. code-block:: bash
-
-    # .env.test
-    MAILER_DSN=null://null
-
 .. note::
 
     If you're using Messenger and routing to a transport, the message will *still*