diff --git a/tests/src/Functional/ExampleMailTest.php b/tests/src/Functional/ExampleMailTest.php
index 4c477ae..f25c3f3 100644
--- a/tests/src/Functional/ExampleMailTest.php
+++ b/tests/src/Functional/ExampleMailTest.php
@@ -5,6 +5,8 @@ namespace Drupal\Tests\swiftmailer\Functional;
 use Drupal\Core\Url;
 
 /**
+ * ExampleMailTest File.
+ *
  * @group swiftmailer
  */
 class ExampleMailTest extends SwiftMailerTestBase {
@@ -15,7 +17,8 @@ class ExampleMailTest extends SwiftMailerTestBase {
   public function testForm() {
     $account = $this->createUser(['administer swiftmailer']);
     $this->drupalLogin($account);
-    $this->drupalPostForm(Url::fromRoute('swiftmailer.test'), [], 'Send');
+    $this->drupalGet(Url::fromRoute('swiftmailer.test'));
+    $this->submitForm([], 'Send');
     $this->assertSession()->pageTextContains(t('An attempt has been made to send an e-mail to @email.', ['@email' => $account->getEmail()]));
     $this->assertBodyContains('The module has been successfully configured.');
   }
diff --git a/tests/src/Functional/RealMailTest.php b/tests/src/Functional/RealMailTest.php
index 41ca102..5d1cb9f 100644
--- a/tests/src/Functional/RealMailTest.php
+++ b/tests/src/Functional/RealMailTest.php
@@ -26,16 +26,20 @@ class RealMailTest extends SwiftMailerTestBase {
       ->set('password_reset.subject', 'You forgot <again>')
       ->set('password_reset.body', '#Your password for [site:name] is a&<b<#')
       ->save();
-    $this->drupalPostForm('user/password', ['name' => $account->getEmail()], 'Submit');
-    $this->assertSubject('You forgot ');
+    $this->drupalGet('user/password');
+    $this->submitForm(['name' => $account->getEmail()], 'Submit');
+    $this->assertSubject('You forgot');
     // @todo Should be $this->assertSubject('You forgot <again>');
     $this->assertBodyContains('#Your password for Rise &amp;amp; shine is a&amp;&lt;b&lt;#');
+
     // @todo Should be $this->assertBodyContains('#Your password for Rise &amp; shine is a&amp;&lt;b&lt;#');
 
     // Plain text.
     $this->enablePlain();
-    $this->drupalPostForm('user/password', ['name' => $account->getEmail()], 'Submit');
+    $this->drupalGet('user/password');
+    $this->submitForm(['name' => $account->getEmail()], 'Submit');
     $this->assertBodyContains('#Your password for Rise &amp; shine is a&<b<#');
+
     // @todo Should be $this->assertBodyContains('#Your password for Rise & shine is a&<b<#');
 
     // Account notification message.
@@ -59,7 +63,8 @@ class RealMailTest extends SwiftMailerTestBase {
       'selected' => TRUE,
     ];
     $this->drupalLogin($this->createUser(['administer contact forms', 'access site-wide contact form']));
-    $this->drupalPostForm('admin/structure/contact/add', $edit, 'Save');
+    $this->drupalGet('admin/structure/contact/add');
+    $this->submitForm($edit, 'Save');
 
     $edit = [
       'subject[0][value]' => 'Hello & greetings',
@@ -67,15 +72,19 @@ class RealMailTest extends SwiftMailerTestBase {
     ];
 
     // HTML.
-    $this->drupalPostForm('contact/contact', $edit, 'Send message');
+    $this->drupalGet('contact/contact');
+    $this->submitForm($edit, 'Send message');
     $this->assertSubject('[Help & Support] Hello & greetings');
     $this->assertBodyContains('#I am so happy <grin>#');
+
     // @todo Should be $this->assertBodyContains('#I am so happy &lt;grin&gt;#');
 
     // Plain text.
     $this->enablePlain();
-    $this->drupalPostForm('contact/contact', $edit, 'Send message');
-    $this->assertBodyContains('#I am so happy #');
+    $this->drupalGet('contact/contact');
+    $this->submitForm($edit, 'Send message');
+    $this->assertBodyContains('#I am so happy#');
+
     // @todo Should be $this->assertBodyContains('#I am so happy <grin>#');
 
   }
diff --git a/tests/src/FunctionalJavascript/SwiftMailerSettingsTest.php b/tests/src/FunctionalJavascript/SwiftMailerSettingsTest.php
index c117b3a..9ffa8b6 100644
--- a/tests/src/FunctionalJavascript/SwiftMailerSettingsTest.php
+++ b/tests/src/FunctionalJavascript/SwiftMailerSettingsTest.php
@@ -30,7 +30,7 @@ class SwiftMailerSettingsTest extends WebDriverTestBase {
   /**
    * The user object.
    *
-   * @var \Drupal\user\UserInterface.
+   * @var \Drupal\user\UserInterface
    */
   protected $adminUser;
 
@@ -126,7 +126,7 @@ class SwiftMailerSettingsTest extends WebDriverTestBase {
     $this->clickLink('Messages');
     $this->assertSession()->pageTextContains('Content type');
 
-    $this->drupalPostForm(NULL, [
+    $this->submitForm([
       'content_type[type]' => 'text/html',
       'generate_plain[mode]' => TRUE,
       'character_set[type]' => 'EUC-CN',