Add test

Author: michaelnabil230

src/Response.php

@@ -388,7 +388,7 @@ public function resolveOnceProps(Request $request): array
             ? App::call($this->oncePropsResolver, ['request' => $request])
             : [];
 
-        return ['onceProps' => $onceProps];
+        return empty($onceProps) ? [] : ['onceProps' => $onceProps];
     }
 
     /**

tests/MiddlewareTest.php

@@ -12,6 +12,7 @@
 use Inertia\AlwaysProp;
 use Inertia\Inertia;
 use Inertia\Middleware;
+use Inertia\Tests\Stubs\CustomOncePropsResolverMiddleware;
 use Inertia\Tests\Stubs\CustomUrlResolverMiddleware;
 use Inertia\Tests\Stubs\ExampleMiddleware;
 use LogicException;
@@ -146,6 +147,19 @@ public function test_the_url_can_be_resolved_with_a_custom_resolver()
         ]);
     }
 
+    public function test_the_once_props_can_be_resolved_with_a_custom_resolver()
+    {
+        $this->prepareMockEndpoint(middleware: new CustomOncePropsResolverMiddleware);
+
+        $response = $this->withoutExceptionHandling()->get('/');
+
+        $response->assertSuccessful();
+        $this->assertSame(
+            '<div id="app" data-page="{&quot;component&quot;:&quot;User\/Edit&quot;,&quot;props&quot;:{&quot;errors&quot;:{},&quot;user&quot;:{&quot;name&quot;:&quot;Jonathan&quot;}},&quot;url&quot;:&quot;\/&quot;,&quot;version&quot;:&quot;&quot;,&quot;clearHistory&quot;:false,&quot;encryptHistory&quot;:false,&quot;onceProps&quot;:{&quot;once&quot;:true,&quot;appName&quot;:&quot;test&quot;}}"></div>',
+            $response->content(),
+        );
+    }
+
     public function test_validation_errors_are_registered_as_of_default(): void
     {
         Route::middleware([StartSession::class, ExampleMiddleware::class])->get('/', function () {

tests/Stubs/CustomOncePropsResolverMiddleware.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Inertia\Tests\Stubs;
+
+use Illuminate\Http\Request;
+use Illuminate\Routing\ResponseFactory;
+use Inertia\Middleware;
+use PHPUnit\Framework\Assert;
+
+class CustomOncePropsResolverMiddleware extends Middleware
+{
+    public function oncePropsResolver()
+    {
+        return function ($request, ResponseFactory $otherDependency) {
+            Assert::assertInstanceOf(Request::class, $request);
+            Assert::assertInstanceOf(ResponseFactory::class, $otherDependency);
+
+            return [
+                'once' => true,
+                'appName' => 'test',
+            ];
+        };
+    }
+}