diff --git a/core/modules/system/tests/modules/form_test/form_test.info.yml b/core/modules/system/tests/modules/form_test/form_test.info.yml
index 3d4280e..2c83010 100644
--- a/core/modules/system/tests/modules/form_test/form_test.info.yml
+++ b/core/modules/system/tests/modules/form_test/form_test.info.yml
@@ -4,4 +4,4 @@ description: 'Support module for Form API tests.'
 package: Testing
 version: VERSION
 core: 8.x
-hidden: true
+hidden: FALSE
diff --git a/core/modules/system/tests/modules/form_test/form_test.routing.yml b/core/modules/system/tests/modules/form_test/form_test.routing.yml
index 2940195..08168fa 100644
--- a/core/modules/system/tests/modules/form_test/form_test.routing.yml
+++ b/core/modules/system/tests/modules/form_test/form_test.routing.yml
@@ -88,7 +88,7 @@ form_test.double_form:
 form_test.alter_form:
   path: '/form-test/alter'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestAlterForm'
+    _content: '\Drupal\form_test\Form\FormTestForm::alterForm'
     _title: 'Form altering test'
   requirements:
     _access: 'TRUE'
@@ -224,7 +224,7 @@ form_test.select:
 form_test.empty_select:
   path: '/form-test/empty-select'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestEmptySelect'
+    _content: '\Drupal\form_test\Form\FormTestForm::testEmptySelect'
     _title: 'Empty Select Element'
   requirements:
     _access: 'TRUE'
@@ -280,7 +280,7 @@ form_test.range_invalid:
 form_test.color:
   path: '/form-test/color'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestColor'
+    _content: '\Drupal\form_test\Form\FormTestForm::testColor'
     _title: 'Color'
   requirements:
     _access: 'TRUE'
@@ -288,7 +288,7 @@ form_test.color:
 form_test.checkboxes_radios:
   path: '/form-test/checkboxes-radios/{customize}'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestCheckboxesRadios'
+    _content: '\Drupal\form_test\Form\FormTestForm::testCheckboxesRadios'
     _title: 'Checkboxes, Radios'
     customize: FALSE
   requirements:
@@ -297,7 +297,7 @@ form_test.checkboxes_radios:
 form_test.email:
   path: '/form-test/email'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestEmail'
+    _content: '\Drupal\form_test\Form\FormTestForm::testEmail'
     _title: 'E-Mail fields'
   requirements:
     _access: 'TRUE'
@@ -361,7 +361,7 @@ form_test.state_persistence:
 form_test.clicked_button:
   path: '/form-test/clicked-button/{first}/{second}/{third}'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestClickedButton'
+    _content: '\Drupal\form_test\Form\FormTestForm::testClickedButton'
     _title: 'Clicked button test'
     first: NULL
     second: NULL
@@ -372,7 +372,7 @@ form_test.clicked_button:
 form_test.checkboxes_zero:
   path: '/form-test/checkboxes-zero/{json}'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestCheckboxesZero'
+    _content: '\Drupal\form_test\Form\FormTestForm::testCheckboxesZero'
     _title: 'FAPI test involving checkboxes and zero'
     json: TRUE
   requirements:
@@ -389,7 +389,7 @@ form_test.required:
 form_test.button_class:
   path: '/form-test/button-class'
   defaults:
-    _form: '\Drupal\form_test\Form\FormTestButtonClass'
+    _content: '\Drupal\form_test\Form\FormTestForm::testButtonClass'
     _title: 'Button class testing'
   requirements:
     _access: 'TRUE'
diff --git a/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/Form/FormTestForm.php b/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/Form/FormTestForm.php
index 6fa4ab0..94c6f0e 100644
--- a/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/Form/FormTestForm.php
+++ b/core/modules/system/tests/modules/form_test/lib/Drupal/form_test/Form/FormTestForm.php
@@ -22,24 +22,6 @@ public function alterForm() {
   }
 
   /**
-   * Wraps form_test_validate_form().
-   *
-   * @todo Remove form_test_validate_form().
-   */
-  public function validateForm() {
-    return drupal_get_form('form_test_validate_form');
-  }
-
-  /**
-   * Wraps form_test_validate_required_form().
-   *
-   * @todo Remove form_test_validate_required_form().
-   */
-  public function validateRequiredForm() {
-    return drupal_get_form('form_test_validate_required_form');
-  }
-
-  /**
    * Wraps form_test_validate_required_form_no_title().
    *
    * @todo Remove form_test_validate_required_form_no_title().
@@ -49,24 +31,6 @@ public function validateRequiredFormNoTitle() {
   }
 
   /**
-   * Wraps form_test_limit_validation_errors_form().
-   *
-   * @todo Remove form_test_limit_validation_errors_form().
-   */
-  public function validateFormWithErrorSuppression() {
-    return drupal_get_form('form_test_limit_validation_errors_form');
-  }
-
-  /**
-   * Wraps form_test_pattern_form().
-   *
-   * @todo Remove form_test_pattern_form().
-   */
-  public function validatePattern() {
-    return drupal_get_form('form_test_pattern_form');
-  }
-
-  /**
    * Wraps _form_test_tableselect_multiple_true_form().
    *
    * @todo Remove _form_test_tableselect_multiple_true_form().