diff --git a/app/Form/Actions/IsDirtyAction.php b/app/Form/Actions/IsDirtyAction.php
index d2b53fa4..68df1a6b 100644
--- a/app/Form/Actions/IsDirtyAction.php
+++ b/app/Form/Actions/IsDirtyAction.php
@@ -11,6 +11,13 @@ class IsDirtyAction
 {
     use AsAction;
 
+    public function rules(): array
+    {
+        return [
+            'config' => 'array|present',
+        ];
+    }
+
     public function handle(Form $form, ActionRequest $request): JsonResponse
     {
         $form->config = $request->input('config');
diff --git a/app/Form/Fields/TextField.php b/app/Form/Fields/TextField.php
index b4668402..71c7abe6 100644
--- a/app/Form/Fields/TextField.php
+++ b/app/Form/Fields/TextField.php
@@ -23,9 +23,9 @@ class TextField extends Field
         ];
     }
 
-    public static function default(): string
+    public static function default(): ?string
     {
-        return '';
+        return null;
     }
 
     public static function fake(Generator $faker): array
diff --git a/tests/Feature/Form/FormtemplateFieldRequest.php b/tests/Feature/Form/FormtemplateFieldRequest.php
index c950a633..6df96889 100644
--- a/tests/Feature/Form/FormtemplateFieldRequest.php
+++ b/tests/Feature/Form/FormtemplateFieldRequest.php
@@ -39,7 +39,7 @@ class FormtemplateFieldRequest extends RequestFactory
             'columns' => ['mobile' => 2, 'tablet' => 4, 'desktop' => 6],
             'nami_type' => null,
             'for_members' => true,
-            'hint' => '',
+            'hint' => null,
         ];
     }
 
diff --git a/tests/Feature/Form/FormtemplateIndexActionTest.php b/tests/Feature/Form/FormtemplateIndexActionTest.php
index a165dac0..dd86b922 100644
--- a/tests/Feature/Form/FormtemplateIndexActionTest.php
+++ b/tests/Feature/Form/FormtemplateIndexActionTest.php
@@ -54,7 +54,7 @@ class FormtemplateIndexActionTest extends TestCase
                     'name' => '',
                     'type' => 'TextField',
                     'columns' => ['mobile' => 2, 'tablet' => 4, 'desktop' => 6],
-                    'value' => '',
+                    'value' => null,
                     'nami_type' => null,
                     'for_members' => true,
                     'special_type' => null,
diff --git a/tests/Feature/Form/IsDirtyActionTest.php b/tests/Feature/Form/IsDirtyActionTest.php
new file mode 100644
index 00000000..a425ed3d
--- /dev/null
+++ b/tests/Feature/Form/IsDirtyActionTest.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Tests\Feature\Form;
+
+use App\Form\Models\Form;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+
+class IsDirtyActionTest extends FormTestCase
+{
+    use DatabaseTransactions;
+
+    public function testItChecksIfFormIsDirty(): void
+    {
+        $this->login()->loginNami();
+        $form = Form::factory()->fields([
+            $this->textField(),
+        ])->create();
+
+        $this->postJson(route('form.is-dirty', ['form' => $form]), ['config' => $form->config->toArray()])->assertJsonPath('result', false);
+
+        $modifiedConfig = $form->config->toArray();
+        data_set($modifiedConfig, 'sections.0.name', 'mod');
+        $this->postJson(route('form.is-dirty', ['form' => $form]), ['config' => $modifiedConfig])->assertJsonPath('result', true);
+    }
+}