[12.x] Add assertRedirectBackWithErrors to TestResponse (#55987)

* Add assertRedirectBackWithErrors to TestResponse

* wip

* wip

* wip

* formatting

---------

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

Author: AhmedAlaa4611

src/Illuminate/Testing/TestResponse.php

@@ -245,6 +245,37 @@ public function assertRedirectBack()
         return $this;
     }
 
+    /**
+     * Assert whether the response is redirecting back to the previous location and the session has the given errors.
+     *
+     * @param  string|array  $keys
+     * @param  mixed  $format
+     * @param  string  $errorBag
+     * @return $this
+     */
+    public function assertRedirectBackWithErrors($keys = [], $format = null, $errorBag = 'default')
+    {
+        $this->assertRedirectBack();
+
+        $this->assertSessionHasErrors($keys, $format, $errorBag);
+
+        return $this;
+    }
+
+    /**
+     * Assert whether the response is redirecting back to the previous location with no errors in the session.
+     *
+     * @return $this
+     */
+    public function assertRedirectBackWithoutErrors()
+    {
+        $this->assertRedirectBack();
+
+        $this->assertSessionHasNoErrors();
+
+        return $this;
+    }
+
     /**
      * Assert whether the response is redirecting to a given route.
      *