diff --git a/message_subscribe_email/src/EventSubscriber/FlagEvents.php b/message_subscribe_email/src/EventSubscriber/FlagEvents.php
index 46fe3d4..2904c0d 100644
--- a/message_subscribe_email/src/EventSubscriber/FlagEvents.php
+++ b/message_subscribe_email/src/EventSubscriber/FlagEvents.php
@@ -99,10 +99,10 @@ protected function triggerEmailFlag(FlaggingInterface $flagging, $action) {
         if (!$flag) {
           throw new MessageSubscribeException('There is no corresponding email flag (' . $email_flag_name . ') for the ' . $flagging->getFlagId() . ' flag.');
         }
-        if ($action == 'flag') {
+        if ($action === 'flag') {
           $this->flagService->flag($flag, $flagging->getFlaggable(), $flagging->getOwner());
         }
-        elseif ($flag->isFlagged($flagging->getFlaggable(), $flagging->getOwner())) {
+        elseif ($this->flagService->getFlagging($flag, $flagging->getFlaggable(), $flagging->getOwner())) {
           $this->flagService->unflag($flag, $flagging->getFlaggable(), $flagging->getOwner());
         }
       }
diff --git a/message_subscribe_email/tests/src/FunctionalJavascript/MessageSubscribeEmailTest.php b/message_subscribe_email/tests/src/FunctionalJavascript/MessageSubscribeEmailTest.php
new file mode 100644
index 0000000..aa2049a
--- /dev/null
+++ b/message_subscribe_email/tests/src/FunctionalJavascript/MessageSubscribeEmailTest.php
@@ -0,0 +1,91 @@
+<?php
+
+namespace Drupal\Tests\message_subscribe_email\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\JavascriptTestBase;
+
+/**
+ * Javascript tests for message subscribe email.
+ *
+ * @group message_subscribe_email
+ */
+class MessageSubscribeEmailTest extends JavascriptTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['message_subscribe_email', 'node'];
+
+  /**
+   * Flag service.
+   *
+   * @var \Drupal\flag\FlagServiceInterface
+   */
+  protected $flagService;
+
+  /**
+   * Nodes to test with.
+   *
+   * @var \Drupal\node\NodeInterface[]
+   */
+  protected $nodes;
+
+  /**
+   * Users to test with.
+   *
+   * @var \Drupal\user\UserInterface[]
+   */
+  protected $users;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+
+    // Add some nodes.
+    $type = $this->createContentType();
+    foreach (range(1, 3) as $i) {
+      $this->nodes[$i] = $this->drupalCreateNode(['type' => $type->id()]);
+    }
+
+    // Add some users.
+    $permissions = [
+      'flag subscribe_node',
+      'unflag subscribe_node',
+      'flag email_node',
+      'unflag email_node',
+    ];
+
+    $this->users[1] = $this->createUser($permissions);
+    $this->users[2] = $this->createUser($permissions);
+    $this->users[3] = $this->createUser($permissions);
+
+    $this->flagService = $this->container->get('flag');
+  }
+
+  /**
+   * Tests the flag/unflag UI.
+   */
+  public function testUi() {
+    $flag = $this->flagService->getFlagById('subscribe_node');
+    $this->drupalLogin($this->users[2]);
+    $this->drupalGet($this->nodes[2]->toUrl());
+
+    // Subscribe to the node.
+    $this->clickLink(t('Subscribe'));
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertTrue($this->flagService->getFlagging($flag, $this->nodes[2], $this->users[2]));
+
+    // Unsubscribe from the node.
+    $this->clickLink(t('Unsubscribe'));
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertFalse($this->flagService->getFlagging($flag, $this->nodes[2], $this->users[2]));
+
+    // Subscribe again!
+    $this->clickLink(t('Subscribe'));
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertTrue($this->flagService->getFlagging($flag, $this->nodes[2], $this->users[2]));
+  }
+
+}