diff --git a/core/modules/action/src/Tests/BulkFormTest.php b/core/modules/action/src/Tests/BulkFormTest.php
index 8fd634b..86c34d0 100644
--- a/core/modules/action/src/Tests/BulkFormTest.php
+++ b/core/modules/action/src/Tests/BulkFormTest.php
@@ -19,6 +19,11 @@
 class BulkFormTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to install.
    *
    * @var array
diff --git a/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml b/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml
index 296a33a..37b4285 100644
--- a/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml
+++ b/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - action
   - views
+  - node
diff --git a/core/modules/block/src/Tests/BlockUiTest.php b/core/modules/block/src/Tests/BlockUiTest.php
index e03135f..0313443 100644
--- a/core/modules/block/src/Tests/BlockUiTest.php
+++ b/core/modules/block/src/Tests/BlockUiTest.php
@@ -17,6 +17,11 @@
 class BlockUiTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to install.
    *
    * @var array
diff --git a/core/modules/block/tests/modules/block_test/config/schema/block_test.schema.yml b/core/modules/block/tests/modules/block_test/config/schema/block_test.schema.yml
new file mode 100644
index 0000000..e0b13cb
--- /dev/null
+++ b/core/modules/block/tests/modules/block_test/config/schema/block_test.schema.yml
@@ -0,0 +1,7 @@
+block.settings.test_block_instantiation:
+  type: block_settings
+  label: 'Test block instantiation settings'
+  mapping:
+    display_message:
+      type: string
+      label: 'Message text'
diff --git a/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
index d4c1372..d7c6d9f 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorAdminTest.php
@@ -19,6 +19,11 @@
 class CKEditorAdminTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to enable.
    *
    * @var array
@@ -154,8 +159,7 @@ function testExistingFormat() {
     $this->drupalGet('admin/config/content/formats/manage/filtered_html');
     $expected_settings['toolbar']['rows'][0][] = array(
       'name' => 'Action history',
-      'items' => array('Undo', '|', 'Redo'),
-      array('JustifyCenter')
+      'items' => array('Undo', '|', 'Redo', 'JustifyCenter'),
     );
     $edit = array(
       'editor[settings][toolbar][button_groups]' => json_encode($expected_settings['toolbar']['rows']),
diff --git a/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php b/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
index 37e047c..23cd3c2 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
@@ -17,6 +17,11 @@
 class CKEditorLoadingTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to enable.
    *
    * @var array
diff --git a/core/modules/color/color.module b/core/modules/color/color.module
index e9cc0a6..390af48 100644
--- a/core/modules/color/color.module
+++ b/core/modules/color/color.module
@@ -60,7 +60,8 @@ function color_form_system_theme_settings_alter(&$form, FormStateInterface $form
     );
     $form['color'] += color_scheme_form($form, $form_state, $theme);
     $form['#validate'][] = 'color_scheme_form_validate';
-    $form['#submit'][] = 'color_scheme_form_submit';
+    // Ensure color submission happens first so we can unset extra values.
+    array_unshift($form['#submit'], 'color_scheme_form_submit');
   }
 }
 
@@ -337,21 +338,26 @@ function color_scheme_form_validate($form, FormStateInterface $form_state) {
  */
 function color_scheme_form_submit($form, FormStateInterface $form_state) {
 
-  // Get theme coloring info.
-  if (!$form_state->hasValue('info')) {
+  // Avoid color settings spilling over to theme settings.
+  $color_settings = array('theme', 'palette', 'scheme');
+  if ($form_state->hasValue('info')) {
+    $color_settings[] = 'info';
+  }
+  foreach ($color_settings as $setting_name) {
+    ${$setting_name} = $form_state->getValue($setting_name);
+    $form_state->unsetValue($setting_name);
+  }
+  if (!isset($info)) {
     return;
   }
-  $theme = $form_state->getValue('theme');
-  $info = $form_state->getValue('info');
 
   $config = \Drupal::config('color.theme.' . $theme);
 
   // Resolve palette.
-  $palette = $form_state->getValue('palette');
-  if ($form_state->getValue('scheme') != '') {
+  if ($scheme != '') {
     foreach ($palette as $key => $color) {
-      if (isset($info['schemes'][$form_state->getValue('scheme')]['colors'][$key])) {
-        $palette[$key] = $info['schemes'][$form_state->getValue('scheme')]['colors'][$key];
+      if (isset($info['schemes'][$scheme]['colors'][$key])) {
+        $palette[$key] = $info['schemes'][$scheme]['colors'][$key];
       }
     }
     $palette += $info['schemes']['default']['colors'];
diff --git a/core/modules/color/src/Tests/ColorConfigSchemaTest.php b/core/modules/color/src/Tests/ColorConfigSchemaTest.php
index bb1e03c..01f3646 100644
--- a/core/modules/color/src/Tests/ColorConfigSchemaTest.php
+++ b/core/modules/color/src/Tests/ColorConfigSchemaTest.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\color\Tests;
 
-use Drupal\config\Tests\SchemaCheckTestTrait;
 use Drupal\simpletest\WebTestBase;
 
 /**
@@ -17,7 +16,10 @@
  */
 class ColorConfigSchemaTest extends WebTestBase {
 
-  use SchemaCheckTestTrait;
+  /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
 
   /**
    * Modules to install.
@@ -53,7 +55,6 @@ function testValidColorConfigSchema() {
     $edit['scheme'] = '';
     $edit['palette[bg]'] = '#123456';
     $this->drupalPostForm($settings_path, $edit, t('Save configuration'));
-    $this->assertConfigSchema(\Drupal::service('config.typed'), 'color.theme.bartik', \Drupal::config('color.theme.bartik')->get());
   }
 
 }
diff --git a/core/modules/color/src/Tests/ColorTest.php b/core/modules/color/src/Tests/ColorTest.php
index 185faae..8adc7f2 100644
--- a/core/modules/color/src/Tests/ColorTest.php
+++ b/core/modules/color/src/Tests/ColorTest.php
@@ -18,6 +18,11 @@
 class ColorTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to install.
    *
    * @var array
diff --git a/core/modules/color/tests/modules/color_test/themes/color_test_theme/config/schema/color_test_theme.schema.yml b/core/modules/color/tests/modules/color_test/themes/color_test_theme/config/schema/color_test_theme.schema.yml
new file mode 100644
index 0000000..33c19d6
--- /dev/null
+++ b/core/modules/color/tests/modules/color_test/themes/color_test_theme/config/schema/color_test_theme.schema.yml
@@ -0,0 +1,5 @@
+# Schema for the configuration files of the Color test theme.
+
+color_test_theme.settings:
+  type: theme_settings
+  label: 'Color test theme settings'
diff --git a/core/modules/comment/config/schema/comment.schema.yml b/core/modules/comment/config/schema/comment.schema.yml
index afd6570..9dd0aa5 100644
--- a/core/modules/comment/config/schema/comment.schema.yml
+++ b/core/modules/comment/config/schema/comment.schema.yml
@@ -24,7 +24,7 @@ action.configuration.comment_unpublish_by_keyword_action:
   type: mapping
   label: 'Unpublish comment containing keyword(s) configuration'
   mapping:
-    keyword:
+    keywords:
       type: sequence
       label: 'Keywords'
       sequence:
diff --git a/core/modules/comment/src/Tests/CommentActionsTest.php b/core/modules/comment/src/Tests/CommentActionsTest.php
index a0b50d6..e5443c1 100644
--- a/core/modules/comment/src/Tests/CommentActionsTest.php
+++ b/core/modules/comment/src/Tests/CommentActionsTest.php
@@ -17,6 +17,11 @@
 class CommentActionsTest extends CommentTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to install.
    *
    * @var array
diff --git a/core/modules/editor/src/Tests/EditorAdminTest.php b/core/modules/editor/src/Tests/EditorAdminTest.php
index ab79287..d4b880c 100644
--- a/core/modules/editor/src/Tests/EditorAdminTest.php
+++ b/core/modules/editor/src/Tests/EditorAdminTest.php
@@ -17,6 +17,11 @@
 class EditorAdminTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to enable.
    *
    * @var array
diff --git a/core/modules/image/config/schema/image.schema.yml b/core/modules/image/config/schema/image.schema.yml
index 7da7c47..87f38f6 100644
--- a/core/modules/image/config/schema/image.schema.yml
+++ b/core/modules/image/config/schema/image.schema.yml
@@ -28,6 +28,10 @@ image.style.*:
       sequence:
         - type: image_style.third_party.[%key]
 
+image.effect.*:
+  type: mapping
+  label: 'Effect settings'
+
 image.effect.image_crop:
   type: image_size
   label: 'Image crop'
diff --git a/core/modules/image/src/Tests/ImageDimensionsTest.php b/core/modules/image/src/Tests/ImageDimensionsTest.php
index 4d6c76b..2b05757 100644
--- a/core/modules/image/src/Tests/ImageDimensionsTest.php
+++ b/core/modules/image/src/Tests/ImageDimensionsTest.php
@@ -17,6 +17,11 @@
 class ImageDimensionsTest extends WebTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to enable.
    *
    * @var array
diff --git a/core/modules/search/src/Tests/SearchTokenizerTest.php b/core/modules/search/src/Tests/SearchTokenizerTest.php
index 66777b3..23338e3 100644
--- a/core/modules/search/src/Tests/SearchTokenizerTest.php
+++ b/core/modules/search/src/Tests/SearchTokenizerTest.php
@@ -14,6 +14,12 @@
  * @group search
  */
 class SearchTokenizerTest extends SearchTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
   /**
    * Verifies that strings of CJK characters are tokenized.
    *
@@ -114,7 +120,7 @@ function testNoTokenizer() {
     // Set the minimum word size to 1 (to split all CJK characters) and make
     // sure CJK tokenizing is turned on.
     \Drupal::config('search.settings')
-      ->set('minimum_word_size', 1)
+      ->set('index.minimum_word_size', 1)
       ->set('overlap_cjk', TRUE)
       ->save();
     $this->refreshVariables();
diff --git a/core/modules/statistics/config/schema/statistics.schema.yml b/core/modules/statistics/config/schema/statistics.schema.yml
index 58f262d..51da9ab 100644
--- a/core/modules/statistics/config/schema/statistics.schema.yml
+++ b/core/modules/statistics/config/schema/statistics.schema.yml
@@ -34,3 +34,17 @@ statistics.settings:
             top_recent_limit:
               type: integer
               label: 'Number of most recent views to display'
+
+block.settings.statistics_popular_block:
+  type: block_settings
+  label: 'Popular content block settings'
+  mapping:
+    top_day_num:
+      type: integer
+      label: 'Number of day\s top views to display'
+    top_all_num:
+      type: integer
+      label: 'Number of all time views to display'
+    top_last_num:
+      type: integer
+      label: 'Number of most recent views to display'
diff --git a/core/modules/statistics/src/Tests/StatisticsReportsTest.php b/core/modules/statistics/src/Tests/StatisticsReportsTest.php
index e3218cf..ed8ba14 100644
--- a/core/modules/statistics/src/Tests/StatisticsReportsTest.php
+++ b/core/modules/statistics/src/Tests/StatisticsReportsTest.php
@@ -15,6 +15,11 @@
 class StatisticsReportsTest extends StatisticsTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Tests the "popular content" block.
    */
   function testPopularContentBlock() {
diff --git a/core/modules/taxonomy/src/Tests/VocabularyCrudTest.php b/core/modules/taxonomy/src/Tests/VocabularyCrudTest.php
index 6cc1678..8ab9ebb 100644
--- a/core/modules/taxonomy/src/Tests/VocabularyCrudTest.php
+++ b/core/modules/taxonomy/src/Tests/VocabularyCrudTest.php
@@ -18,6 +18,11 @@
 class VocabularyCrudTest extends TaxonomyTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to enable.
    *
    * @var array
diff --git a/core/modules/tour/src/Tests/TourTest.php b/core/modules/tour/src/Tests/TourTest.php
index 8ed261c..ee8ea7b 100644
--- a/core/modules/tour/src/Tests/TourTest.php
+++ b/core/modules/tour/src/Tests/TourTest.php
@@ -17,6 +17,11 @@
 class TourTest extends TourTestBasic {
 
   /**
+   * {@inheritdoc}
+   */
+  protected $strictConfigSchema = TRUE;
+
+  /**
    * Modules to enable.
    *
    * @var array