More tests.

tests/integration/TestPermanentDismissinleNotice.php

@@ -5,6 +5,8 @@ use \WPDesk\Notice\PermanentDismissibleNotice;
 class TestPermanentDismissinleNotice extends WP_UnitTestCase
 {
 
+    const NOTICE_NAME = 'test_notice_name';
+
     public function testAddAction()
     {
         $notice_priority = 11;
@@ -19,6 +21,23 @@ class TestPermanentDismissinleNotice extends WP_UnitTestCase
         $this->assertEquals($notice_priority, has_action('admin_notices', [$notice, 'showNotice'], $notice_priority));
     }
 
+    public function testUndoDismiss()
+    {
+        update_option(PermanentDismissibleNotice::OPTION_NAME_PREFIX . self::NOTICE_NAME, PermanentDismissibleNotice::OPTION_VALUE_DISMISSED);
+
+        $notice = new PermanentDismissibleNotice(
+            PermanentDismissibleNotice::NOTICE_TYPE_INFO,
+            'test',
+            self::NOTICE_NAME
+        );
+        $notice->undoDismiss();
+
+        $this->assertEquals(
+            '',
+            get_option(PermanentDismissibleNotice::OPTION_NAME_PREFIX . self::NOTICE_NAME, '')
+        );
+    }
+
     public function testShowNotice()
     {
         $notice = new PermanentDismissibleNotice(