diff -u b/modules/webform_ajax/tests/src/FunctionalJavascript/WebformAjaxTest.php b/modules/webform_ajax/tests/src/FunctionalJavascript/WebformAjaxTest.php
--- b/modules/webform_ajax/tests/src/FunctionalJavascript/WebformAjaxTest.php
+++ b/modules/webform_ajax/tests/src/FunctionalJavascript/WebformAjaxTest.php
@@ -10,7 +10,6 @@
  *
  * @group webform_ajax
  *
- * @todo Test the back link.
  * @todo This lumps a number of different tests together. AJAX is quite a cross-
  *   cutting concern and I'd welcome input on how best to slice up the tests.
  */
@@ -30,9 +29,8 @@
     $webform = $this->provider->webformWithTextfield();
     $webform->setSetting('confirmation_type', 'message');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
-    $this->drupalPostForm($path, ['textfield' => 'test value'], t('Submit'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield' => 'test value'], t('Submit'));
     $element = $assert->waitForElement('css', '.messages--status');
 
     $this->assertNotNull($element, "An AJAX submission shows a confirmation message.");
@@ -49,7 +47,6 @@
     $webform = $this->provider->webformWithTextfield();
     $webform->setSetting('confirmation_type', 'inline');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     // @todo Use an API call to get the form ID.
     $form_id = 'webform_submission_' . $webform->id() . '_form';
     // The inline confirmation message is wrapped in the same wrapper the form
@@ -58,7 +55,7 @@
     $locator = "#webform-ajax-$form_id .webform-confirmation";
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield' => 'test value'], t('Submit'));
+    $this->drupalPostForm($webform->toUrl()->getInternalPath(), ['textfield' => 'test value'], t('Submit'));
     $element = $assert->waitForElement('css', $locator);
 
     $this->assertNotNull($element, "An AJAX submission shows an inline confirmation message.");
@@ -73,10 +70,9 @@
     $webform = $this->provider->webformWithTextfield();
     $webform->setSetting('confirmation_type', 'message');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield' => 'test value'], t('Submit'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield' => 'test value'], t('Submit'));
     $assert->waitForElement('css', '.messages--status');
     $this->drupalPostForm(NULL, ['textfield' => 'test value 2'], t('Submit'));
     // I'm not sure there's an element I can wait on.
@@ -97,10 +93,9 @@
     $webform = $this->provider->webformWithTextfield();
     $webform->setSetting('confirmation_type', 'message');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield' => 'test value'], t('Submit'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield' => 'test value'], t('Submit'));
     $assert->waitForElement('css', '.messages--status');
     /** @var \Drupal\webform\WebformSubmissionStorageInterface $storage */
     $storage = \Drupal::entityTypeManager()->getStorage('webform_submission');
@@ -117,10 +112,9 @@
     $webform = $this->provider->webformWithTextfield(['#required' => TRUE]);
     $webform->setSetting('confirmation_type', 'message');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield' => ''], t('Submit'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield' => ''], t('Submit'));
     $element = $assert->waitForElement('css', '.messages--error');
 
     $this->assertNotNull($element, "An AJAX submission triggers server-side validation errors.");
@@ -134,10 +128,9 @@
     $webform = $this->provider->webformWithTextfield();
     $webform->setSetting('confirmation_type', 'message');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield' => 'test value'], t('Submit'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield' => 'test value'], t('Submit'));
     $assert->waitForElement('css', '.messages--warning');
     $this->drupalPostForm(NULL, ['textfield' => 'test value 2'], t('Submit'));
     $assert->assertWaitOnAjaxRequest();
@@ -154,10 +147,9 @@
     $webform = $this->provider->multipageWebformWithTextfields();
     $webform->setSetting('confirmation_type', 'message');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield_1' => 'test value page 1'], t('Next Page >'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield_1' => 'test value page 1'], t('Next Page >'));
     $element = $assert->waitForButton('Submit');
 
     $this->assertNotNull($element, "An AJAX submission on the first page of a multi-page form causes the next page to show");
@@ -174,16 +166,17 @@
 
   /**
    * Test the back link.
+   *
+   * @todo: Incorpate this into another test.
    */
   public function testBackLink() {
     // For now use the test_element_text webform as an easy check.
     $webform = $this->provider->webformWithTextfield();
     $webform->setSetting('confirmation_type', 'inline');
     $webform->save();
-    $path = $webform->toUrl()->getInternalPath();
     $assert = $this->assertSession();
 
-    $this->drupalPostForm($path, ['textfield' => 'test value'], t('Submit'));
+    $this->drupalPostForm($webform->toUrl(), ['textfield' => 'test value'], t('Submit'));
     $back_link = $assert->waitForLink('Back to form');
 
     $this->assertNotNull($back_link, "An AJAX submission confirmation shows a 'Back to form' link.");
diff -u b/modules/webform_ajax/webform_ajax.module b/modules/webform_ajax/webform_ajax.module
--- b/modules/webform_ajax/webform_ajax.module
+++ b/modules/webform_ajax/webform_ajax.module
@@ -51,7 +51,7 @@
   // AJAX submissions only make sense with certain kinds of confirmation.
   // @todo Disable the AJAX setting in the UI based on the confirmation type.
   $confirmation_type = $webform->getSetting('confirmation_type');
-  if (!in_array($confirmation_type, ['message', 'inline'])) {
+  if (!in_array($confirmation_type, ['message', 'inline'], TRUE)) {
     return;
   }
 
@@ -84,24 +84,21 @@
 
   $response = new AjaxResponse();
   $output = [];
-  $confirmation_type = $webform->getSetting('confirmation_type');
-  if ($submission->getState() == WebformSubmissionInterface::STATE_COMPLETED) {
-    switch ($confirmation_type) {
-      case 'message':
-        // Currently the message set by webform itself is being squashed by
-        // \Drupal\webform\WebformMessageManager::display() with an explicit
-        // AJAX check..
-        // @todo: Neaten this up
-        _webform_display_confirmation_message($submission);
-        $output = _webform_ajax_get_fresh_submission_form($webform);
-        break;
-
-      case 'inline':
-        $confirmation = webform_ajax_confirmation_message($submission, $element_id);
-        // Add the same wrapper as the form (messages go above it, and it gets
-        // replaced when clicking the back link).
-        $output = _webform_ajax_wrap_element($confirmation, $element_id);
-        break;
+    if ($submission->getState() == WebformSubmissionInterface::STATE_COMPLETED) {
+    $confirmation_type = $webform->getSetting('confirmation_type');
+    if ($confirmation_type === 'message') {
+      // Currently the message set by webform itself is being squashed by
+      // \Drupal\webform\WebformMessageManager::display() with an explicit
+      // AJAX check..
+      // @todo: Neaten this up
+      _webform_display_confirmation_message($submission);
+      $output = _webform_ajax_get_fresh_submission_form($webform);
+    }
+    elseif ($confirmation_type === 'inline') {
+      $confirmation = webform_ajax_confirmation_message($submission, $element_id);
+      // Add the same wrapper as the form (messages go above it, and it gets
+      // replaced when clicking the back link).
+      $output = _webform_ajax_wrap_element($confirmation, $element_id);
     }
   }
   else {
@@ -166,7 +163,6 @@
  */
 function webform_ajax_confirmation_message(WebformSubmissionInterface $submission, $element_id) {
   $webform = $submission->getWebform();
-  /** @var \Drupal\webform\WebformMessageManagerInterface $message_manager */
   $source_entity = $submission->getSourceEntity();
   $url = Url::fromRoute('webform_ajax.return_webform', [
     'webform' => $webform->id(),
reverted:
--- b/webform.info.yml
+++ a/webform.info.yml
@@ -8,5 +8,3 @@
   - 'drupal:field'
   - 'drupal:system (>= 8.2)'
   - 'drupal:user'
-test_dependencies:
-  - webform_ajax