diff --git a/core/modules/editor/tests/modules/config/schema/editor_test.schema.yml b/core/modules/editor/tests/modules/config/schema/editor_test.schema.yml
new file mode 100644
index 0000000..6900e2f
--- /dev/null
+++ b/core/modules/editor/tests/modules/config/schema/editor_test.schema.yml
@@ -0,0 +1,9 @@
+# Schema for the configuration files of the Editor test module.
+
+editor.settings.unicorn:
+  type: mapping
+  label: 'Unicorn settings'
+  mapping:
+    ponies_too:
+      type: string
+      label: 'Ponies too'
diff --git a/core/modules/editor/src/Tests/EditorAdminTest.php b/core/modules/editor/src/Tests/EditorAdminTest.php
index e133a26..1e72494 100644
--- a/core/modules/editor/src/Tests/EditorAdminTest.php
+++ b/core/modules/editor/src/Tests/EditorAdminTest.php
@@ -154,7 +154,7 @@ protected function verifyUnicornEditorConfiguration($format_id, $foo = 'bar') {
     $settings = $editor->getSettings();
     $this->assertIdentical($editor->getEditor(), 'unicorn', 'The text editor is configured correctly.');
     $this->assertIdentical($settings['foo'], $foo, 'The text editor settings are stored correctly.');
-    $this->assertIdentical($settings['ponies too'], true, 'The text editor defaults are retrieved correctly.');
+    $this->assertIdentical($settings['ponies_too'], true, 'The text editor defaults are retrieved correctly.');
     $this->assertIdentical($settings['rainbows'], true, 'The text editor defaults added by hook_editor_settings_defaults() are retrieved correctly.');
     $this->assertIdentical($settings['sparkles'], false, 'The text editor defaults modified by hook_editor_settings_defaults_alter() are retrieved correctly.');
     $this->drupalGet('admin/config/content/formats/manage/'. $format_id);
diff --git a/core/modules/editor/tests/modules/src/Plugin/Editor/UnicornEditor.php b/core/modules/editor/tests/modules/src/Plugin/Editor/UnicornEditor.php
index fcc2c90..49644e5 100644
--- a/core/modules/editor/tests/modules/src/Plugin/Editor/UnicornEditor.php
+++ b/core/modules/editor/tests/modules/src/Plugin/Editor/UnicornEditor.php
@@ -28,7 +28,7 @@ class UnicornEditor extends EditorBase {
    * {@inheritdoc}
    */
   function getDefaultSettings() {
-    return array('ponies too' => TRUE);
+    return array('ponies_too' => TRUE);
   }
 
   /**
@@ -49,7 +49,7 @@ function settingsForm(array $form, FormStateInterface $form_state, EditorEntity
   function getJSSettings(EditorEntity $editor) {
     $js_settings = array();
     $settings = $editor->getSettings();
-    if ($settings['ponies too']) {
+    if ($settings['ponies_too']) {
       $js_settings['ponyModeEnabled'] = TRUE;
     }
     return $js_settings;