diff --git a/resources/build.defaults.yaml b/resources/build.defaults.yaml
index 8de91e4..dc1f09e 100644
--- a/resources/build.defaults.yaml
+++ b/resources/build.defaults.yaml
@@ -2,6 +2,7 @@ drupal:
   docroot: web
 
 experimental:
+  runStaticAnalysisOnTests: false
   useNewDatabaseCredentials: true
 
 project_root: /app
diff --git a/src/DataTransferObject/Config.php b/src/DataTransferObject/Config.php
index b25973c..6a9f38b 100644
--- a/src/DataTransferObject/Config.php
+++ b/src/DataTransferObject/Config.php
@@ -120,6 +120,10 @@ final class Config
                 new Assert\Type('bool'),
             ]),
 
+            'runStaticAnalysisOnTests' => new Assert\Optional([
+                new Assert\Type('bool'),
+            ]),
+
             // TODO: remove this when its been removed from all `build.yaml` files.
             'useNewDatabaseCredentials' => new Assert\Optional([
                 new Assert\Type('bool'),
diff --git a/templates/drupal/phpstan.neon.dist.twig b/templates/drupal/phpstan.neon.dist.twig
index a4abb27..4bd4c2e 100644
--- a/templates/drupal/phpstan.neon.dist.twig
+++ b/templates/drupal/phpstan.neon.dist.twig
@@ -2,9 +2,11 @@
 
 parameters:
   level: {{ php.phpstan.level }}
+{% if not experimental.runStaticAnalysisOnTests %}
   excludePaths:
     - *Test.php
     - *TestBase.php
+{% endif %}
   paths:
     {% for path in php.phpstan.paths -%}
     - {{ path }}