minor #14917 [Testing] [PHPUnit-Bridge] Troubleshooting (sylfabre)

This PR was submitted for the 5.4 branch but it was merged into the 4.4 branch instead.

Discussion
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[Testing] [PHPUnit-Bridge] Troubleshooting

This PR documents a new solution to an issue I'm having with ClockMock related to https://bugs.php.net/bug.php?id=76788.

I was the original author of the current Troubleshooting section and came across another use-case

Commits
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8e162de [PHPUnit-Bridge] Troubleshooting

Author: javiereguiluz

components/phpunit_bridge.rst

@@ -789,24 +789,42 @@ namespaces in the ``phpunit.xml`` file, as done for example in the
 
 Under the hood, a PHPUnit listener injects the mocked functions in the tested
 classes' namespace. In order to work as expected, the listener has to run before
-the tested class ever runs. By default, the mocked functions are created when the
-annotation are found and the corresponding tests are run. Depending on how your
-tests are constructed, this might be too late. In this case, you will need to declare
-the namespaces of the tested classes in your ``phpunit.xml.dist``.
+the tested class ever runs.
+
+By default, the mocked functions are created when the annotation are found and
+the corresponding tests are run. Depending on how your tests are constructed,
+this might be too late.
+
+You can either:
+* Declare the namespaces of the tested classes in your ``phpunit.xml.dist``.
+* Register the namespaces at the end of the ``config/bootstrap.php`` file.
 
 .. code-block:: xml
 
     <!-- phpunit.xml.dist -->
-    <!-- ... -->
-    <listeners>
-        <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener">
-                <arguments>
-                    <array>
-                        <element key="time-sensitive"><string>Acme\MyClassTest</string></element>
-                    </array>
-                </arguments>
-            </listener>
-    </listeners>
+    <phpunit
+        bootstrap="config/bootstrap.php"
+    >
+        <!-- ... -->
+        <listeners>
+            <listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener">
+                    <arguments>
+                        <array>
+                            <element key="time-sensitive"><string>Acme\MyClassTest</string></element>
+                        </array>
+                    </arguments>
+                </listener>
+        </listeners>
+    </phpunit>
+
+.. code-block:: php
+
+    <!-- config/bootstrap.php -->
+    use Symfony\Bridge\PhpUnit\ClockMock;
+    
+    if ('test' === $_SERVER['APP_ENV']) {
+        ClockMock::register('Acme\\MyClassTest\\');
+    }
 
 Modified PHPUnit script
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