diff --git a/doc/creating-a-language-target.md b/doc/creating-a-language-target.md
index 365a091539..723b865f2c 100644
--- a/doc/creating-a-language-target.md
+++ b/doc/creating-a-language-target.md
@@ -68,3 +68,14 @@ Run the script from `runtime-tests` dir with
 ```
 
 or whatever your test grammar, start rule, target, test input are.
+
+### Debugging the PHP target
+
+Because the PHP target is hosted in a separate repository, you will need to clone the [antlr/php-antlr-runtime](https://github.com/antlr/antlr-php-runtime)
+repository into the `runtime/PHP` and install the dependencies with `composer install` before you can run the tests.
+
+```
+git clone -b dev https://github.com/antlr/antlr-php-runtime.git runtime/PHP
+cd runtime/PHP
+composer install
+```
diff --git a/runtime-testsuite/resources/org/antlr/v4/test/runtime/helpers/Test.php.stg b/runtime-testsuite/resources/org/antlr/v4/test/runtime/helpers/Test.php.stg
index 2222ce556d..c4c33f2284 100644
--- a/runtime-testsuite/resources/org/antlr/v4/test/runtime/helpers/Test.php.stg
+++ b/runtime-testsuite/resources/org/antlr/v4/test/runtime/helpers/Test.php.stg
@@ -17,8 +17,10 @@ use Antlr\Antlr4\Runtime\Tree\TerminalNode;
 
 $runtime = \getenv('RUNTIME');
 
+require_once $runtime . '/vendor/autoload.php';
+
 \spl_autoload_register(function (string $class) use ($runtime) : void {
-    $file = \str_replace('\\\', \DIRECTORY_SEPARATOR, \str_replace('Antlr\Antlr4\Runtime\\\', $runtime . '\\\src\\\', $class)) . '.php';
+    $file = \str_replace('\\\', \DIRECTORY_SEPARATOR, $class) . '.php';
 
     if (\file_exists($file)) {
         require_once $file;