diff --git a/tests/modules/fillpdf_test/fillpdf_test.module b/tests/modules/fillpdf_test/fillpdf_test.module
index 1897fa55c9dc65e3eb1999341a768d99fb977d47..cf37bd0f6e7332de3308f5f25752e90fd6206d7e 100644
--- a/tests/modules/fillpdf_test/fillpdf_test.module
+++ b/tests/modules/fillpdf_test/fillpdf_test.module
@@ -20,7 +20,7 @@ function fillpdf_test_form_fillpdf_settings_alter(array &$form, FormStateInterfa
   $form['example_setting'] = [
     '#type' => 'textfield',
     '#title' => 'Form-altered example setting',
-    '#default_value' => \Drupal::config('fillpdf.settings')->get('example_setting'),
+    '#default_value' => \Drupal::config('fillpdf_test.settings')->get('example_setting'),
     '#states' => [
       'visible' => [
         ':input[name="backend"]' => ['value' => 'test'],
@@ -53,7 +53,7 @@ function fillpdf_test_form_fillpdf_settings_submit($form, FormStateInterface $fo
   if ($form_state->getValue('backend') == 'test' && $value = $form_state->getValue('example_setting')) {
     /** @var \Drupal\Core\Config\ConfigFactoryInterface $config_factory */
     $config_factory = \Drupal::service('config.factory');
-    $config_factory->getEditable('fillpdf.settings')->set('example_setting', $value)->save();
+    $config_factory->getEditable('fillpdf_test.settings')->set('example_setting', $value)->save();
   }
 }
 
diff --git a/tests/src/Functional/FillPdfSettingsFormTest.php b/tests/src/Functional/FillPdfSettingsFormTest.php
index c21f77f0603466b7250b8e126b9f9a41fb614a10..b57dbeaa62922aa5ccf03067d43ffbc4c5bac18a 100644
--- a/tests/src/Functional/FillPdfSettingsFormTest.php
+++ b/tests/src/Functional/FillPdfSettingsFormTest.php
@@ -245,7 +245,8 @@ class FillPdfSettingsFormTest extends BrowserTestBase {
     // Therefore, the new values should be submitted, but *not* saved.
     foreach ($edit as $field => $value) {
       $this->assertSession()->fieldValueEquals($field, $value);
-      $this->assertEqual($this->config('fillpdf.settings')->get($field), NULL);
+      $config_name = $field === 'example_setting' ? 'fillpdf_test.settings' : 'fillpdf.settings';
+      $this->assertEqual($this->config($config_name)->get($field), NULL);
     }
 
     // Try again with a valid value.
@@ -260,7 +261,8 @@ class FillPdfSettingsFormTest extends BrowserTestBase {
     $expected = ['fillpdf_service_api_key' => NULL] + $edit;
     foreach ($expected as $field => $value) {
       $this->assertSession()->fieldValueEquals($field, $value);
-      $this->assertEqual($this->config('fillpdf.settings')->get($field), $value);
+      $config_name = $field === 'example_setting' ? 'fillpdf_test.settings' : 'fillpdf.settings';
+      $this->assertEqual($this->config($config_name)->get($field), $value);
     }
   }