diff --git a/patchwork.json b/patchwork.json
new file mode 100644
index 0000000..6cf722c
--- /dev/null
+++ b/patchwork.json
@@ -0,0 +1,3 @@
+{
+  "redefinable-internals": ["function_exists"]
+}
diff --git a/tests/FieldGroupTest.php b/tests/FieldGroupTest.php
index 06b850d..5f587f6 100644
--- a/tests/FieldGroupTest.php
+++ b/tests/FieldGroupTest.php
@@ -16,4 +16,14 @@ final class FieldGroupTest extends TestCase
             'FieldGroup::register() must hook acf/init'
         );
     }
+
+    public function test_do_register_is_noop_when_acf_missing(): void
+    {
+        \Brain\Monkey\Functions\when('function_exists')->justReturn(false);
+        \Brain\Monkey\Functions\expect('acf_add_local_field_group')->never();
+
+        FieldGroup::do_register();
+
+        self::assertTrue(true, 'do_register must not call acf_add_local_field_group when ACF is missing');
+    }
 }