[8.x] Add merge() function to ValidatedInput (#38640)

* Add `merge()` function

* Add test for `merge()` function

* Fix the test

* Update ValidatedInput.php

* Update ValidatedInputTest.php

Co-authored-by: Taylor Otwell <taylor@laravel.com>

src/Illuminate/Support/ValidatedInput.php

@@ -68,6 +68,17 @@ public function except($keys)
         return $results;
     }
 
+    /**
+     * Merge the validated input with the given array of additional data.
+     *
+     * @param  array  $items
+     * @return static
+     */
+    public function merge(array $items)
+    {
+        return new static(array_merge($this->input, $items));
+    }
+
     /**
      * Get the input as a collection.
      *

tests/Support/ValidatedInputTest.php

@@ -17,4 +17,17 @@ public function test_can_access_input()
         $this->assertEquals(['name' => 'Taylor'], $input->except(['votes']));
         $this->assertEquals(['name' => 'Taylor', 'votes' => 100], $input->all());
     }
+
+    public function test_can_merge_items()
+    {
+        $input = new ValidatedInput(['name' => 'Taylor']);
+
+        $input = $input->merge(['votes' => 100]);
+
+        $this->assertEquals('Taylor', $input->name);
+        $this->assertEquals('Taylor', $input['name']);
+        $this->assertEquals(['name' => 'Taylor'], $input->only(['name']));
+        $this->assertEquals(['name' => 'Taylor'], $input->except(['votes']));
+        $this->assertEquals(['name' => 'Taylor', 'votes' => 100], $input->all());
+    }
 }