Add simplePaginate append test

Author: francoism90

tests/AppendTest.php

@@ -5,6 +5,7 @@
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Http\Request;
 use Illuminate\Pagination\LengthAwarePaginator;
+use Illuminate\Pagination\Paginator;
 use Illuminate\Support\Collection;
 use Spatie\QueryBuilder\Exceptions\InvalidAppendQuery;
 use Spatie\QueryBuilder\QueryBuilder;
@@ -159,4 +160,14 @@ protected function assertPaginateAttributeLoaded(LengthAwarePaginator $collectio
 
         $this->assertFalse($hasModelWithoutAttributeLoaded, "The `{$attribute}` attribute was expected but not loaded.");
     }
+
+    protected function assertSimplePaginateAttributeLoaded(Paginator $collection, string $attribute)
+    {
+        $hasModelWithoutAttributeLoaded = $collection
+            ->contains(function (Model $model) use ($attribute) {
+                return ! array_key_exists($attribute, $model->toArray());
+            });
+
+        $this->assertFalse($hasModelWithoutAttributeLoaded, "The `{$attribute}` attribute was expected but not loaded.");
+    }
 }