diff --git a/tests/src/Functional/CommentNotifyConfigPageTest.php b/tests/src/Functional/CommentNotifyConfigPageTest.php
index dfed112..5e0e5b9 100644
--- a/tests/src/Functional/CommentNotifyConfigPageTest.php
+++ b/tests/src/Functional/CommentNotifyConfigPageTest.php
@@ -28,10 +28,117 @@ protected function setUp() {
    * Test to all the options are saved correctly.
    */
   public function testConfigPage() {
-    // Check the default values are working.
     $this->drupalGet("admin/config/people/comment_notify");
+
+    // Test the default values are working.
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+
+    // Test that the content types are saved correctly.
+    $this->getSession()->getPage()->checkField('node_types[article]');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hasCheckedField('node_types[article]'));
+
+    // Test that Available subscription modes are saved correctly.
+    $this->getSession()->getPage()->checkField('available_alerts[1]');
+    $this->getSession()->getPage()->checkField('available_alerts[2]');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hasCheckedField('available_alerts[1]'));
+    $this->assertTrue($this->getSession()->getPage()->hasCheckedField('available_alerts[2]'));
+
+    // Test that at least one subscription mode must be enabled.
+    $this->getSession()->getPage()->uncheckField('available_alerts[1]');
+    $this->getSession()->getPage()->uncheckField('available_alerts[2]');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('You must enable at least one subscription mode.');
+
+    $this->getSession()->getPage()->uncheckField('available_alerts[1]');
+    $this->getSession()->getPage()->checkField('available_alerts[2]');
     $this->submitForm([], 'Save configuration');
     $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hasUncheckedField('available_alerts[1]'));
+    $this->assertTrue($this->getSession()->getPage()->hascheckedField('available_alerts[2]'));
+    // The default state select must hide the option as well.
+    $field = $this->getSession()->getPage()->findField('Default state for the notification selection box');
+    $this->assertFalse(strpos($field->getHtml(), 'All Comments'));
+    $this->assertTrue(strpos($field->getHtml(), 'Replies to my comment'));
+
+    $this->getSession()->getPage()->uncheckField('available_alerts[2]');
+    $this->getSession()->getPage()->checkField('available_alerts[1]');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hasUncheckedField('available_alerts[2]'));
+    $this->assertTrue($this->getSession()->getPage()->hascheckedField('available_alerts[1]'));
+    // The default state select must hide the option as well.
+    $field = $this->getSession()->getPage()->findField('Default state for the notification selection box');
+    $this->assertTrue(strpos($field->getHtml(), 'All comments'));
+    $this->assertFalse(strpos($field->getHtml(), 'Replies to my comment'));
+
+    $this->getSession()->getPage()->checkField('available_alerts[1]');
+    $this->getSession()->getPage()->checkField('available_alerts[2]');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hascheckedField('available_alerts[1]'));
+    $this->assertTrue($this->getSession()->getPage()->hascheckedField('available_alerts[2]'));
+    $field = $this->getSession()->getPage()->findField('Default state for the notification selection box');
+    $this->assertTrue(strpos($field->getHtml(), 'All comments'));
+    $this->assertTrue(strpos($field->getHtml(), 'Replies to my comment'));
+
+    $this->getSession()->getPage()->selectFieldOption('Default state for the notification selection box', "0");
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $field = $this->getSession()->getPage()->findField('Default state for the notification selection box');
+    $this->assertTrue($field->getValue() == "0");
+
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->getSession()->getPage()->selectFieldOption('Default state for the notification selection box', "1");
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $field = $this->getSession()->getPage()->findField('Default state for the notification selection box');
+    $this->assertTrue($field->getValue() == "1");
+
+    $this->getSession()->getPage()->selectFieldOption('Default state for the notification selection box', "2");
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $field = $this->getSession()->getPage()->findField('Default state for the notification selection box');
+    $this->assertTrue($field->getValue() == "2");
+
+    $this->getSession()->getPage()->checkField('Subscribe users to their node follow-up notification emails by default');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hasCheckedField('Subscribe users to their node follow-up notification emails by default'));
+
+    $this->getSession()->getPage()->uncheckField('Subscribe users to their node follow-up notification emails by default');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $this->assertTrue($this->getSession()->getPage()->hasUncheckedField('Subscribe users to their node follow-up notification emails by default'));
+
+    $this->getSession()->getPage()->fillField('Default mail text for sending out notifications to commenters', 'Hello');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $field = $this->getSession()->getPage()->findField('Default mail text for sending out notifications to commenters');
+    $this->assertTrue($field->getValue() == 'Hello');
+
+    $this->getSession()->getPage()->fillField('Default mail text for sending out the notifications to node authors', 'Hello');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->responseContains('The configuration options have been saved.');
+    $this->drupalGet("admin/config/people/comment_notify");
+    $field = $this->getSession()->getPage()->findField('Default mail text for sending out the notifications to node authors');
+    $this->assertTrue($field->getValue() == 'Hello');
+
   }
 
 }