diff --git a/infection.json b/infection.json
index 14366950..56f5a96c 100644
--- a/infection.json
+++ b/infection.json
@@ -17,5 +17,11 @@
         "stryker": {
             "report": "1.x"
         }
+    },
+    "mutators": {
+        "@default": true,
+        "global-ignoreSourceCodeByRegex": [
+            "#\\[TestInline"
+        ]
     }
 }
diff --git a/tests/Application/Stub/EmptyRun/.placeholder.php b/tests/Application/Stub/EmptyRun/.placeholder.php
new file mode 100644
index 00000000..72680edf
--- /dev/null
+++ b/tests/Application/Stub/EmptyRun/.placeholder.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+// Intentionally empty — fixture directory for EmptyRunTest.
+// This file exists solely so the PHPUnit mirror build (bin/build-phpunit.php)
+// copies it to tests/PhpUnit/Application/Stub/EmptyRun/, creating the directory
+// that the mirrored EmptyRunTest references via __DIR__ . '/../../Stub/EmptyRun'.
+// The file contains no classes or tests; the Testo application run in the test
+// finds zero tests here and correctly reports Status::Risky.