docs: split sample code file

Author: kenjis

user_guide_src/source/testing/overview.rst

@@ -124,6 +124,8 @@ logged in user:
 
 .. literalinclude:: overview/006.php
 
+.. literalinclude:: overview/022.php
+
 Additional Assertions
 ---------------------
 

user_guide_src/source/testing/overview/006.php

@@ -12,12 +12,3 @@ protected function setUpAuthTrait()
 
     // ...
 }
-
-use CodeIgniter\Test\CIUnitTestCase;
-
-final class AuthenticationFeatureTest extends CIUnitTestCase
-{
-    use AuthTrait;
-
-    // ...
-}

user_guide_src/source/testing/overview/022.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Tests;
+
+use App\Traits\AuthTrait;
+use CodeIgniter\Test\CIUnitTestCase;
+
+final class AuthenticationFeatureTest extends CIUnitTestCase
+{
+    use AuthTrait;
+
+    // ...
+}