diff -u b/core/modules/media/media.module b/core/modules/media/media.module
--- b/core/modules/media/media.module
+++ b/core/modules/media/media.module
@@ -52,7 +52,7 @@
  *
  * Fix broken operations array in field UI for entities with restricted access.
  *
- * @todo: This hook can be removed when issue 2836384 is fixed.
+ * @todo This hook can be removed when issue #2836384 is done.
  * @see https://www.drupal.org/node/2836384
  */
 function media_entity_operation_alter(array &$operations, EntityInterface $entity) {
diff -u b/core/modules/media/src/Entity/Media.php b/core/modules/media/src/Entity/Media.php
--- b/core/modules/media/src/Entity/Media.php
+++ b/core/modules/media/src/Entity/Media.php
@@ -2,10 +2,10 @@
 
 namespace Drupal\media\Entity;
 
-use Drupal\Core\Entity\ContentEntityBase;
 use Drupal\Core\Entity\EntityPublishedTrait;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Entity\RevisionableContentEntityBase;
 use Drupal\Core\Field\BaseFieldDefinition;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Drupal\media\MediaInterface;
@@ -17,7 +17,7 @@
 /**
  * Defines the media entity class.
  *
- * @todo Remove default/fallback entity form operation when #2006348 lands.
+ * @todo Remove default/fallback entity form operation when #2006348 is done.
  * @see https://www.drupal.org/node/2006348.
  *
  * @ContentEntityType(
@@ -77,7 +77,7 @@
  *   }
  * )
  */
-class Media extends ContentEntityBase implements MediaInterface {
+class Media extends RevisionableContentEntityBase implements MediaInterface {
 
   use EntityChangedTrait;
   use EntityPublishedTrait;
@@ -299,17 +299,17 @@
     parent::preSaveRevision($storage, $record);
 
     $is_new_revision = $this->isNewRevision();
-    if (!$is_new_revision && isset($this->original) && empty($record->revision_log)) {
+    if (!$is_new_revision && isset($this->original) && empty($record->revision_log_message)) {
       // If we are updating an existing media item without adding a
-      // new revision, we need to make sure $entity->revision_log is reset
-      // whenever it is empty.
+      // new revision, we need to make sure $entity->revision_log_message is
+      // reset whenever it is empty.
       // Therefore, this code allows us to avoid clobbering an existing log
       // entry with an empty one.
-      $record->revision_log = $this->original->revision_log->value;
+      $record->revision_log_message = $this->original->revision_log_message->value;
     }
 
     if ($is_new_revision) {
-      $record->revision_timestamp = self::getRequestTime();
+      $record->revision_created = self::getRequestTime();
     }
   }
 
@@ -422,34 +422,6 @@
       ->setTranslatable(TRUE)
       ->setRevisionable(TRUE);
 
-    $fields['revision_timestamp'] = BaseFieldDefinition::create('created')
-      ->setLabel(t('Revision timestamp'))
-      ->setDescription(t('The time the current revision was created.'))
-      ->setQueryable(FALSE)
-      ->setRevisionable(TRUE);
-
-    $fields['revision_uid'] = BaseFieldDefinition::create('entity_reference')
-      ->setLabel(t('Revision authored by'))
-      ->setDescription(t('The user ID of the author of the current revision.'))
-      ->setDefaultValueCallback(static::class . '::getCurrentUserId')
-      ->setSetting('target_type', 'user')
-      ->setQueryable(FALSE)
-      ->setRevisionable(TRUE);
-
-    $fields['revision_log'] = BaseFieldDefinition::create('string_long')
-      ->setLabel(t('Revision Log'))
-      ->setDescription(t('The log entry explaining the changes in this revision.'))
-      ->setRevisionable(TRUE)
-      ->setTranslatable(TRUE)
-      ->setDefaultValue('')
-      ->setDisplayOptions('form', [
-        'type' => 'string_textarea',
-        'weight' => 25,
-        'settings' => [
-          'rows' => 4,
-        ],
-      ]);
-
     return $fields;
   }
 
@@ -474,62 +446,2 @@
 
-  /**
-   * {@inheritdoc}
-   */
-  public function getRevisionCreationTime() {
-    return $this->revision_timestamp->value;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setRevisionCreationTime($timestamp) {
-    $this->revision_timestamp->value = $timestamp;
-    return $this;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getRevisionUser() {
-    return $this->revision_uid->entity;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setRevisionUser(UserInterface $account) {
-    $this->revision_uid->entity = $account;
-    return $this;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getRevisionUserId() {
-    return $this->revision_uid->target_id;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setRevisionUserId($user_id) {
-    $this->revision_uid->target_id = $user_id;
-    return $this;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getRevisionLogMessage() {
-    return $this->revision_log->value;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setRevisionLogMessage($revision_log_message) {
-    $this->revision_log->value = $revision_log_message;
-    return $this;
-  }
-
 }
diff -u b/core/modules/media/src/Form/MediaDeleteMultipleConfirmForm.php b/core/modules/media/src/Form/MediaDeleteMultipleConfirmForm.php
--- b/core/modules/media/src/Form/MediaDeleteMultipleConfirmForm.php
+++ b/core/modules/media/src/Form/MediaDeleteMultipleConfirmForm.php
@@ -16,9 +16,9 @@
 class MediaDeleteMultipleConfirmForm extends ConfirmFormBase {
 
   /**
-   * The array of media items to delete.
+   * The array of media items to delete, indexed by ID and language.
    *
-   * @var array
+   * @var string[][]
    */
   protected $mediaItems = [];
 
@@ -92,7 +92,7 @@
   /**
    * {@inheritdoc}
    *
-   * @todo: Change to trait or base class when #2843395 is done.
+   * @todo Change to trait or base class when #2843395 is done.
    * @see https://www.drupal.org/node/2843395
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
@@ -145,7 +145,7 @@
   /**
    * {@inheritdoc}
    *
-   * @todo: Change to trait or base class when #2843395 is done.
+   * @todo Change to trait or base class when #2843395 is done.
    * @see https://www.drupal.org/node/2843395
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
diff -u b/core/modules/media/src/MediaForm.php b/core/modules/media/src/MediaForm.php
--- b/core/modules/media/src/MediaForm.php
+++ b/core/modules/media/src/MediaForm.php
@@ -91,11 +91,11 @@
 
     // If already published, the 'publish' button is primary.
     if ($media->isPublished()) {
-      unset($element['unpublish']['#button_type']);
+      $element['publish']['#button_type'] = 'primary';
     }
     // Otherwise, the 'unpublish' button is primary and should come first.
     else {
-      unset($element['publish']['#button_type']);
+      $element['unpublish']['#button_type'] = 'primary';
       $element['unpublish']['#weight'] = -10;
     }
 
diff -u b/core/modules/media/src/MediaInterface.php b/core/modules/media/src/MediaInterface.php
--- b/core/modules/media/src/MediaInterface.php
+++ b/core/modules/media/src/MediaInterface.php
@@ -16,6 +16,9 @@
   /**
    * Returns the media item creation timestamp.
    *
+   * @todo Remove and use the new interface when #2833378 is done.
+   * @see https://www.drupal.org/node/2833378
+   *
    * @return int
    *   Creation timestamp of the media item.
    */
@@ -24,6 +27,9 @@
   /**
    * Sets the media item creation timestamp.
    *
+   * @todo Remove and use the new interface when #2833378 is done.
+   * @see https://www.drupal.org/node/2833378
+   *
    * @param int $timestamp
    *   The media creation timestamp.
    *
diff -u b/core/modules/media/src/MediaSourceBase.php b/core/modules/media/src/MediaSourceBase.php
--- b/core/modules/media/src/MediaSourceBase.php
+++ b/core/modules/media/src/MediaSourceBase.php
@@ -76,6 +76,8 @@
     $this->entityFieldManager = $entity_field_manager;
     $this->fieldTypeManager = $field_type_manager;
     $this->configFactory = $config_factory;
+
+    // Add the default configuration of the media source to the plugin.
     $this->setConfiguration($configuration);
   }
 
diff -u b/core/modules/media/src/MediaSourceInterface.php b/core/modules/media/src/MediaSourceInterface.php
--- b/core/modules/media/src/MediaSourceInterface.php
+++ b/core/modules/media/src/MediaSourceInterface.php
@@ -44,8 +44,8 @@
  *   URL or other identifier, while sources that represent local files might
  *   check the MIME type of the file.
  * - Providing a default name for a media item. This will save users from
- *   manually entering the name when it can be reliably set automatically. Media
- *   sources for local files will generally use the filename, while media
+ *   manually entering the name when it can be reliably set automatically.
+ *   Media sources for local files will generally use the filename, while media
  *   sources for remote resources might obtain a title attribute through a
  *   third-party API. The name can always be overridden by the user.
  * - Providing metadata specific to the given media type. For example, remote
@@ -67,6 +67,11 @@
 interface MediaSourceInterface extends PluginInspectionInterface, ConfigurablePluginInterface, PluginFormInterface {
 
   /**
+   * Default empty value for metadata fields.
+   */
+  const METADATA_FIELD_EMPTY = '_none';
+
+  /**
    * Gets a list of metadata attributes provided by this plugin.
    *
    * Most media sources have associated metadata, describing attributes
diff -u b/core/modules/media/src/MediaTypeForm.php b/core/modules/media/src/MediaTypeForm.php
--- b/core/modules/media/src/MediaTypeForm.php
+++ b/core/modules/media/src/MediaTypeForm.php
@@ -60,7 +60,7 @@
    */
   public function ajaxHandlerData(array $form, FormStateInterface $form_state) {
     $response = new AjaxResponse();
-    $response->addCommand(new ReplaceCommand('#source-dependent', $form['source_dependent(']));
+    $response->addCommand(new ReplaceCommand('#source-dependent', $form['source_dependent']));
     return $response;
   }
 
@@ -111,12 +111,12 @@
       $options[$plugin_id] = $definition['label'];
     }
 
-    $form['source_dependent('] = [
+    $form['source_dependent'] = [
       '#type' => 'container',
       '#attributes' => ['id' => 'source-dependent'],
     ];
 
-    $form['source_dependent(']['source'] = [
+    $form['source_dependent']['source'] = [
       '#type' => 'select',
       '#title' => $this->t('Media source'),
       '#default_value' => $source ? $source->getPluginId() : NULL,
@@ -132,17 +132,17 @@
 
     if ($source) {
       // Media source plugin configuration.
-      $form['source_dependent(']['source_configuration'] = [
+      $form['source_dependent']['source_configuration'] = [
         '#type' => 'fieldset',
         '#title' => $this->t('Media source configuration'),
         '#tree' => TRUE,
       ];
 
-      $form['source_dependent(']['source_configuration'] = $source->buildConfigurationForm($form['source_dependent(']['source_configuration'], $this->getSourceSubFormState($form, $form_state));
+      $form['source_dependent']['source_configuration'] = $source->buildConfigurationForm($form['source_dependent']['source_configuration'], $this->getSourceSubFormState($form, $form_state));
     }
 
     // Field mapping configuration.
-    $form['source_dependent(']['field_map'] = [
+    $form['source_dependent']['field_map'] = [
       '#type' => 'fieldset',
       '#title' => $this->t('Field mapping'),
       '#tree' => TRUE,
@@ -152,10 +152,10 @@
     ];
 
     if (empty($source) || empty($source->getMetadataAttributes())) {
-      $form['source_dependent(']['field_map']['#access'] = FALSE;
+      $form['source_dependent']['field_map']['#access'] = FALSE;
     }
     else {
-      $options = ['_none' => $this->t('- Skip field -')];
+      $options = [MediaSourceInterface::METADATA_FIELD_EMPTY => $this->t('- Skip field -')];
       foreach ($this->entityFieldManager->getFieldDefinitions('media', $this->entity->id()) as $field_name => $field) {
         if (!($field instanceof BaseFieldDefinition) || $field_name === 'name') {
           $options[$field_name] = $field->getLabel();
@@ -164,11 +164,11 @@
 
       $field_map = $this->entity->getFieldMap();
       foreach ($source->getMetadataAttributes() as $metadata_attribute_name => $metadata_attribute_label) {
-        $form['source_dependent(']['field_map'][$metadata_attribute_name] = [
+        $form['source_dependent']['field_map'][$metadata_attribute_name] = [
           '#type' => 'select',
           '#title' => $metadata_attribute_label,
           '#options' => $options,
-          '#default_value' => isset($field_map[$metadata_attribute_name]) ? $field_map[$metadata_attribute_name] : '_none',
+          '#default_value' => isset($field_map[$metadata_attribute_name]) ? $field_map[$metadata_attribute_name] : MediaSourceInterface::METADATA_FIELD_EMPTY,
         ];
       }
     }
@@ -247,11 +247,11 @@
    * @param \Drupal\Core\Form\FormStateInterface $form_state
    *   Parent form state.
    *
-   * @return \Drupal\Core\Form\SubFormStateInterface
+   * @return \Drupal\Core\Form\SubformStateInterface
    *   Sub-form state for the media source configuration form.
    */
   protected function getSourceSubFormState(array $form, FormStateInterface $form_state) {
-    return SubformState::createForSubform($form['source_dependent(']['source_configuration'], $form, $form_state)
+    return SubformState::createForSubform($form['source_dependent']['source_configuration'], $form, $form_state)
       ->set('operation', $this->operation)
       ->set('type', $this->entity);
   }
@@ -262,9 +262,9 @@
   public function validateForm(array &$form, FormStateInterface $form_state) {
     parent::validateForm($form, $form_state);
 
-    if ($form['source_dependent(']['source_configuration']) {
+    if ($form['source_dependent']['source_configuration']) {
       // Let the selected plugin validate its settings.
-      $this->entity->getSource()->validateConfigurationForm($form['source_dependent(']['source_configuration'], $this->getSourceSubFormState($form, $form_state));
+      $this->entity->getSource()->validateConfigurationForm($form['source_dependent']['source_configuration'], $this->getSourceSubFormState($form, $form_state));
     }
   }
 
@@ -275,7 +275,7 @@
     $form_state->setValue('field_map', array_filter(
       $form_state->getValue('field_map', []),
       function ($item) {
-        return $item != '_none';
+        return $item != MediaSourceInterface::METADATA_FIELD_EMPTY;
       }
     ));
 
@@ -285,9 +285,9 @@
       ->setStatus((bool) $form_state->getValue(['options', 'status']))
       ->setNewRevision((bool) $form_state->getValue(['options', 'new_revision']));
 
-    if ($form['source_dependent(']['source_configuration']) {
+    if ($form['source_dependent']['source_configuration']) {
       // Let the selected plugin save its settings.
-      $this->entity->getSource()->submitConfigurationForm($form['source_dependent(']['source_configuration'], $this->getSourceSubFormState($form, $form_state));
+      $this->entity->getSource()->submitConfigurationForm($form['source_dependent']['source_configuration'], $this->getSourceSubFormState($form, $form_state));
     }
   }
 
@@ -316,7 +316,6 @@
     $source_field = $source->getSourceFieldDefinition($media_type);
     if (!$source_field) {
       $source_field = $source->createSourceField($media_type);
-
       /** @var \Drupal\field\FieldStorageConfigInterface $storage */
       $storage = $source_field->getFieldStorageDefinition();
       if ($storage->isNew() || !$storage->isLocked()) {
diff -u b/core/modules/media/src/MediaTypeInterface.php b/core/modules/media/src/MediaTypeInterface.php
--- b/core/modules/media/src/MediaTypeInterface.php
+++ b/core/modules/media/src/MediaTypeInterface.php
@@ -78,8 +78,8 @@
    * copied to the corresponding entity fields.
    *
    * @return array
-   *   Field mapping array with fields provided by the type plugin as keys and
-   *   Drupal Entity fields as values.
+   *   Field mapping array provided by media source with metadata attribute
+   *   names as keys and entity field names as values.
    */
   public function getFieldMap();
 
@@ -87,8 +87,8 @@
    * Sets the metadata field map.
    *
    * @param array $map
-   *   Field mapping with metadata attribute names as keys and entity field
-   *   names as values.
+   *   Field mapping array with metadata attribute names as keys and entity
+   *   field names as values.
    *
    * @return $this
    */
diff -u b/core/modules/media/src/Plugin/Field/FieldFormatter/MediaThumbnailFormatter.php b/core/modules/media/src/Plugin/Field/FieldFormatter/MediaThumbnailFormatter.php
--- b/core/modules/media/src/Plugin/Field/FieldFormatter/MediaThumbnailFormatter.php
+++ b/core/modules/media/src/Plugin/Field/FieldFormatter/MediaThumbnailFormatter.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\media\Plugin\Field\FieldFormatter;
 
+use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Session\AccountInterface;
@@ -9,6 +10,7 @@
 use Drupal\image\Plugin\Field\FieldFormatter\ImageFormatter;
 use Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem;
 use Drupal\Core\Render\RendererInterface;
+use Drupal\media\MediaInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\Core\Field\FieldDefinitionInterface;
 
@@ -129,48 +131,31 @@
    */
   public function viewElements(FieldItemListInterface $items, $langcode) {
     $elements = [];
-    $media = $this->getEntitiesToView($items, $langcode);
+    $media_items = $this->getEntitiesToView($items, $langcode);
 
     // Early opt-out if the field is empty.
-    if (empty($media)) {
+    if (empty($media_items)) {
       return $elements;
     }
 
-    $url = NULL;
-    $image_link_setting = $this->getSetting('image_link');
-    // Check if the formatter involves a link.
-    if ($image_link_setting == 'content') {
-      $entity = $items->getEntity();
-      if (!$entity->isNew()) {
-        $url = $entity->toUrl();
-      }
-    }
-    elseif ($image_link_setting === 'media') {
-      $link_media = TRUE;
-    }
-
     $image_style_setting = $this->getSetting('image_style');
 
-    /** @var \Drupal\media\MediaInterface[] $media */
-    foreach ($media as $delta => $media_item) {
-      if (isset($link_media)) {
-        $url = $media_item->toUrl();
-      }
-
+    /** @var \Drupal\media\MediaInterface[] $media_items */
+    foreach ($media_items as $delta => $media) {
       $elements[$delta] = [
         '#theme' => 'image_formatter',
-        '#item' => $media_item->get('thumbnail'),
+        '#item' => $media->get('thumbnail')->first(),
         '#item_attributes' => [],
-        '#image_style' => $image_style_setting,
-        '#url' => $url,
+        '#image_style' => $this->getSetting('image_style'),
+        '#url' => $this->getMediaUrl($media, $items->getEntity()),
       ];
 
       // Add cacheability of each item in the field.
-      $this->renderer->addCacheableDependency($elements[$delta], $media_item);
+      $this->renderer->addCacheableDependency($elements[$delta], $media);
     }
 
     // Add cacheability of the image style setting.
-    if ($image_link_setting && ($image_style = $this->imageStyleStorage->load($image_style_setting))) {
+    if ($this->getSetting('image_link') && ($image_style = $this->imageStyleStorage->load($image_style_setting))) {
       $this->renderer->addCacheableDependency($elements, $image_style);
     }
 
@@ -188,2 +173,29 @@
 
+  /**
+   * Get the URL for the media thumbnail.
+   *
+   * @param \Drupal\media\MediaInterface $media
+   *   The media item.
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity that the field belongs to.
+   *
+   * @return \Drupal\Core\Url|null
+   *   The URL object for the media item or null if we don't want to add
+   *   a link.
+   */
+  protected function getMediaUrl(MediaInterface $media, EntityInterface $entity) {
+    $url = NULL;
+    $image_link_setting = $this->getSetting('image_link');
+    // Check if the formatter involves a link.
+    if ($image_link_setting == 'content') {
+      if (!$entity->isNew()) {
+        $url = $entity->toUrl();
+      }
+    }
+    elseif ($image_link_setting === 'media') {
+      $url = $media->toUrl();
+    }
+    return $url;
+  }
+
 }
diff -u b/core/modules/media/src/Plugin/QueueWorker/ThumbnailDownloader.php b/core/modules/media/src/Plugin/QueueWorker/ThumbnailDownloader.php
--- b/core/modules/media/src/Plugin/QueueWorker/ThumbnailDownloader.php
+++ b/core/modules/media/src/Plugin/QueueWorker/ThumbnailDownloader.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\media\Plugin\QueueWorker;
 
+use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\media\Entity\Media;
 use Drupal\Core\Queue\QueueWorkerBase;
@@ -19,10 +20,27 @@
 class ThumbnailDownloader extends QueueWorkerBase implements ContainerFactoryPluginInterface {
 
   /**
-   * {@inheritdoc}
+   * The entity type manager service.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * Constructs a new class instance.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin_id for the plugin instance.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   Entity type manager service.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
+    $this->entityTypeManager = $entity_type_manager;
   }
 
   /**
@@ -32,7 +50,8 @@
     return new static(
       $configuration,
       $plugin_id,
-      $plugin_definition
+      $plugin_definition,
+      $container->get('entity_type.manager')
     );
   }
 
@@ -40,7 +59,8 @@
    * {@inheritdoc}
    */
   public function processItem($data) {
-    if ($media = Media::load($data['id'])) {
+    /** @var \Drupal\media\Entity\Media $media */
+    if ($media = $this->entityTypeManager->getStorage('media')->load($data['id'])) {
       $media->updateQueuedThumbnail();
       $media->save();
     }
diff -u b/core/modules/media/src/Plugin/views/wizard/Media.php b/core/modules/media/src/Plugin/views/wizard/Media.php
--- b/core/modules/media/src/Plugin/views/wizard/Media.php
+++ b/core/modules/media/src/Plugin/views/wizard/Media.php
@@ -29,7 +29,7 @@
    */
   protected $filters = [
     'status' => [
-      'value' => TRUE,
+      'value' => '1',
       'table' => 'media_field_data',
       'field' => 'status',
       'plugin_id' => 'boolean',
diff -u b/core/modules/media/src/Plugin/views/wizard/MediaRevision.php b/core/modules/media/src/Plugin/views/wizard/MediaRevision.php
--- b/core/modules/media/src/Plugin/views/wizard/MediaRevision.php
+++ b/core/modules/media/src/Plugin/views/wizard/MediaRevision.php
@@ -20,7 +20,7 @@
    *
    * @var string
    */
-  protected $createdColumn = 'created';
+  protected $createdColumn = 'media_field_revision-created';
 
   /**
    * Set default values for the filters.
diff -u b/core/modules/media/tests/modules/media_test_source/src/Plugin/media/Source/Test.php b/core/modules/media/tests/modules/media_test_source/src/Plugin/media/Source/Test.php
--- b/core/modules/media/tests/modules/media_test_source/src/Plugin/media/Source/Test.php
+++ b/core/modules/media/tests/modules/media_test_source/src/Plugin/media/Source/Test.php
@@ -8,7 +8,7 @@
 use Drupal\media\MediaSourceBase;
 
 /**
- * Provides test media type.
+ * Provides test media source.
  *
  * @MediaSource(
  *   id = "test",
@@ -23,6 +23,9 @@
    * {@inheritdoc}
    */
   public function getMetadataAttributes() {
+    // The metadata attributes are kept in state storage. This allows tests to
+    // change the metadata attributes and makes it easier to test different
+    // variations.
     $attributes = \Drupal::state()->get('media_source_test_attributes', [
       'attribute_1' => ['label' => $this->t('Attribute 1'), 'value' => 'Value 1'],
       'attribute_2' => ['label' => $this->t('Attribute 2'), 'value' => 'Value 1'],
diff -u b/core/modules/media/tests/modules/media_test_type/config/install/media.type.test.yml b/core/modules/media/tests/modules/media_test_type/config/install/media.type.test.yml
--- b/core/modules/media/tests/modules/media_test_type/config/install/media.type.test.yml
+++ b/core/modules/media/tests/modules/media_test_type/config/install/media.type.test.yml
@@ -10 +10,2 @@
-field_map: {  }
+field_map:
+  metadata_attribute: 'field_attribute_config_test'
diff -u b/core/modules/media/tests/src/Functional/MediaCacheTagsTest.php b/core/modules/media/tests/src/Functional/MediaCacheTagsTest.php
--- b/core/modules/media/tests/src/Functional/MediaCacheTagsTest.php
+++ b/core/modules/media/tests/src/Functional/MediaCacheTagsTest.php
@@ -15,7 +15,7 @@
  */
 class MediaCacheTagsTest extends EntityWithUriCacheTagsTestBase {
 
-  use MediaFunctionalTestTrait;
+  use MediaFunctionalTestCreateMediaTypeTrait;
 
   /**
    * {@inheritdoc}
diff -u b/core/modules/media/tests/src/Functional/MediaFunctionalTestBase.php b/core/modules/media/tests/src/Functional/MediaFunctionalTestBase.php
--- b/core/modules/media/tests/src/Functional/MediaFunctionalTestBase.php
+++ b/core/modules/media/tests/src/Functional/MediaFunctionalTestBase.php
@@ -10,6 +10,7 @@
 abstract class MediaFunctionalTestBase extends BrowserTestBase {
 
   use MediaFunctionalTestTrait;
+  use MediaFunctionalTestCreateMediaTypeTrait;
 
   /**
    * Modules to enable.
@@ -27,66 +28,2 @@
 
-  /**
-   * Permissions for the admin user that will be logged in for test.
-   *
-   * @var array
-   */
-  protected static $adminUserPermissions = [
-    // Media entity permissions.
-    'administer media',
-    'administer media fields',
-    'administer media form display',
-    'administer media display',
-    'administer media types',
-    'view media',
-    'create media',
-    'update media',
-    'update any media',
-    'delete media',
-    'delete any media',
-    // Other permissions.
-    'administer views',
-    'access content overview',
-    'view all revisions',
-    'administer content types',
-    'administer node fields',
-    'administer node form display',
-    'bypass node access',
-  ];
-
-  /**
-   * An admin test user account.
-   *
-   * @var \Drupal\Core\Session\AccountInterface
-   */
-  protected $adminUser;
-
-  /**
-   * A non-admin test user account.
-   *
-   * @var \Drupal\Core\Session\AccountInterface
-   */
-  protected $nonAdminUser;
-
-  /**
-   * The storage handler.
-   *
-   * @var \Drupal\Core\Entity\EntityStorageInterface
-   */
-  protected $storage;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-
-    // Have two users ready to be used in tests.
-    $this->adminUser = $this->drupalCreateUser(static::$adminUserPermissions);
-    $this->nonAdminUser = $this->drupalCreateUser([]);
-    // Start off logged in as admin.
-    $this->drupalLogin($this->adminUser);
-
-    $this->storage = $this->container->get('entity_type.manager')->getStorage('media');
-  }
-
 }
diff -u b/core/modules/media/tests/src/Functional/MediaFunctionalTestTrait.php b/core/modules/media/tests/src/Functional/MediaFunctionalTestTrait.php
--- b/core/modules/media/tests/src/Functional/MediaFunctionalTestTrait.php
+++ b/core/modules/media/tests/src/Functional/MediaFunctionalTestTrait.php
@@ -2,64 +2,73 @@
 
 namespace Drupal\Tests\media\Functional;
 
-use Drupal\media\Entity\MediaType;
-
 /**
  * Trait with helpers for Media functional tests.
  */
 trait MediaFunctionalTestTrait {
 
   /**
-   * Creates a media type.
+   * Permissions for the admin user that will be logged-in for test.
+   *
+   * @var array
+   */
+  protected static $adminUserPermissions = [
+    // Media entity permissions.
+    'administer media',
+    'administer media fields',
+    'administer media form display',
+    'administer media display',
+    'administer media types',
+    'view media',
+    'create media',
+    'update media',
+    'update any media',
+    'delete media',
+    'delete any media',
+    // Other permissions.
+    'administer views',
+    'access content overview',
+    'view all revisions',
+    'administer content types',
+    'administer node fields',
+    'administer node form display',
+    'bypass node access',
+  ];
+
+  /**
+   * An admin test user account.
+   *
+   * @var \Drupal\Core\Session\AccountInterface
+   */
+  protected $adminUser;
+
+  /**
+   * A non-admin test user account.
    *
-   * @param array $values
-   *   The media type values.
-   * @param string $source
-   *   (optional) The media source plugin that is responsible for additional
-   *   logic related to this media type. Defaults to 'test'.
+   * @var \Drupal\Core\Session\AccountInterface
+   */
+  protected $nonAdminUser;
+
+  /**
+   * The storage service.
    *
-   * @return \Drupal\media\MediaTypeInterface
-   *   A newly created media type.
+   * @var \Drupal\Core\Entity\EntityStorageInterface
    */
-  protected function createMediaType(array $values = [], $source = 'test') {
-    if (empty($values['bundle'])) {
-      $id = strtolower($this->randomMachineName());
-    }
-    else {
-      $id = $values['bundle'];
-    }
-    $values += [
-      'id' => $id,
-      'label' => $id,
-      'source' => $source,
-      'source_configuration' => [],
-      'field_map' => [],
-      'new_revision' => FALSE,
-    ];
-
-    $media_type = MediaType::create($values);
-    $status = $media_type->save();
-
-    $this->assertSame(SAVED_NEW, $status, 'Media type was created successfully.');
-
-    // Ensure that the source field exists.
-    $source = $media_type->getSource();
-    $source_field = $source->getSourceFieldDefinition($media_type);
-    if (!$source_field) {
-      $source_field = $source->createSourceField($media_type);
-      /** @var \Drupal\field\FieldStorageConfigInterface $storage */
-      $storage = $source_field->getFieldStorageDefinition();
-      $storage->setLocked(TRUE)->save();
-      $source_field->save();
-
-      $media_type
-        ->set('source_configuration', [
-          'source_field' => $source_field->getName(),
-        ])
-        ->save();
-    }
+  protected $storage;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    // Have two users ready to be used in tests.
+    $this->adminUser = $this->drupalCreateUser(static::$adminUserPermissions);
+    $this->nonAdminUser = $this->drupalCreateUser([]);
+    // Start off logged in as admin.
+    $this->drupalLogin($this->adminUser);
 
-    return $media_type;
+    $this->storage = $this->container->get('entity_type.manager')->getStorage('media');
   }
 
 }
diff -u b/core/modules/media/tests/src/Functional/MediaUiFunctionalTest.php b/core/modules/media/tests/src/Functional/MediaUiFunctionalTest.php
--- b/core/modules/media/tests/src/Functional/MediaUiFunctionalTest.php
+++ b/core/modules/media/tests/src/Functional/MediaUiFunctionalTest.php
@@ -52,7 +52,7 @@
     $media_name = $this->randomMachineName();
     $page->fillField('name[0][value]', $media_name);
     $revision_log_message = $this->randomString();
-    $page->fillField('revision_log[0][value]', $revision_log_message);
+    $page->fillField('revision_log_message[0][value]', $revision_log_message);
     $page->pressButton('Save and publish');
     $media_id = $this->container->get('entity.query')->get('media')->execute();
     $media_id = reset($media_id);
@@ -61,7 +61,8 @@
       ->getStorage('media')
       ->loadUnchanged($media_id);
     $this->assertEquals($media->getRevisionLogMessage(), $revision_log_message);
-    $assert_session->titleEquals($media->label() . ' | Drupal');
+    $this->assertEquals($media->label(), $media_name);
+    $assert_session->titleEquals($media_name . ' | Drupal');
 
     // Tests media edit form.
     $media_type->setNewRevision(FALSE);
@@ -72,6 +73,11 @@
     $media_name = $this->randomMachineName();
     $page->fillField('name[0][value]', $media_name2);
     $page->pressButton('Save and keep published');
+    /** @var \Drupal\media\MediaInterface $media */
+    $media = $this->container->get('entity_type.manager')
+      ->getStorage('media')
+      ->loadUnchanged($media_id);
+    $this->assertEquals($media->label(), $media_name2);
     $assert_session->titleEquals($media_name2 . ' | Drupal');
 
     // Test that there is no empty vertical tabs element, if the container is
@@ -90,13 +96,13 @@
     $this->drupalLogin($this->adminUser);
 
     // Enable revisions by default.
-    $previoius_revision_id = $media->getRevisionId();
+    $previous_revision_id = $media->getRevisionId();
     $media_type->setNewRevision(TRUE);
     $media_type->save();
     $this->drupalGet('media/' . $media_id . '/edit');
     $assert_session->checkboxChecked('edit-revision');
     $page->fillField('name[0][value]', $media_name);
-    $page->fillField('revision_log[0][value]', $revision_log_message);
+    $page->fillField('revision_log_message[0][value]', $revision_log_message);
     $page->pressButton('Save and keep published');
     $assert_session->titleEquals($media_name . ' | Drupal');
     /** @var \Drupal\media\MediaInterface $media */
@@ -104,7 +110,7 @@
       ->getStorage('media')
       ->loadUnchanged($media_id);
     $this->assertEquals($media->getRevisionLogMessage(), $revision_log_message);
-    $this->assertNotEquals($previoius_revision_id, $media->getRevisionId());
+    $this->assertNotEquals($previous_revision_id, $media->getRevisionId());
 
     // Tests media delete form.
     $this->drupalGet('media/' . $media_id . '/edit');
diff -u b/core/modules/media/tests/src/FunctionalJavascript/MediaJavascriptTestBase.php b/core/modules/media/tests/src/FunctionalJavascript/MediaJavascriptTestBase.php
--- b/core/modules/media/tests/src/FunctionalJavascript/MediaJavascriptTestBase.php
+++ b/core/modules/media/tests/src/FunctionalJavascript/MediaJavascriptTestBase.php
@@ -3,6 +3,7 @@
 namespace Drupal\Tests\media\FunctionalJavascript;
 
 use Drupal\FunctionalJavascriptTests\JavascriptTestBase;
+use Drupal\Tests\media\Functional\MediaFunctionalTestCreateMediaTypeTrait;
 use Drupal\Tests\media\Functional\MediaFunctionalTestTrait;
 
 /**
@@ -11,6 +12,7 @@
 abstract class MediaJavascriptTestBase extends JavascriptTestBase {
 
   use MediaFunctionalTestTrait;
+  use MediaFunctionalTestCreateMediaTypeTrait;
 
   /**
    * Modules to enable.
@@ -27,70 +29,6 @@
   ];
 
   /**
-   * Permissions for the admin user that will be logged-in for test.
-   *
-   * @var array
-   */
-  protected static $adminUserPermissions = [
-    // Media entity permissions.
-    'administer media',
-    'administer media fields',
-    'administer media form display',
-    'administer media display',
-    'administer media types',
-    'view media',
-    'create media',
-    'update media',
-    'update any media',
-    'delete media',
-    'delete any media',
-    // Other permissions.
-    'administer views',
-    'access content overview',
-    'view all revisions',
-    'administer content types',
-    'administer node fields',
-    'administer node form display',
-    'bypass node access',
-  ];
-
-  /**
-   * An admin test user account.
-   *
-   * @var \Drupal\Core\Session\AccountInterface
-   */
-  protected $adminUser;
-
-  /**
-   * A non-admin test user account.
-   *
-   * @var \Drupal\Core\Session\AccountInterface
-   */
-  protected $nonAdminUser;
-
-  /**
-   * The storage service.
-   *
-   * @var \Drupal\Core\Entity\EntityStorageInterface
-   */
-  protected $storage;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-
-    // Have two users ready to be used in tests.
-    $this->adminUser = $this->drupalCreateUser(static::$adminUserPermissions);
-    $this->nonAdminUser = $this->drupalCreateUser([]);
-    // Start off logged in as admin.
-    $this->drupalLogin($this->adminUser);
-
-    $this->storage = $this->container->get('entity_type.manager')->getStorage('media');
-  }
-
-  /**
    * Waits and asserts that a given element is visible.
    *
    * @param string $selector
diff -u b/core/modules/media/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php b/core/modules/media/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php
--- b/core/modules/media/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php
+++ b/core/modules/media/tests/src/FunctionalJavascript/MediaUiJavascriptTest.php
@@ -5,6 +5,7 @@
 use Drupal\field\FieldConfigInterface;
 use Drupal\media\Entity\Media;
 use Drupal\media\Entity\MediaType;
+use Drupal\media\MediaSourceInterface;
 
 /**
  * Ensures that media UI works correctly.
@@ -147,7 +148,7 @@
     $assert_session->checkboxChecked('options[queue_thumbnail_downloads]');
     $assert_session->fieldValueEquals('Test config value', 'This is new config value.');
     $assert_session->fieldValueEquals('Attribute 1', 'name');
-    $assert_session->fieldValueEquals('Attribute 2', '_none');
+    $assert_session->fieldValueEquals('Attribute 2', MediaSourceInterface::METADATA_FIELD_EMPTY);
 
     /** @var \Drupal\media\MediaTypeInterface $loaded_media_type */
     $loaded_media_type = $this->container->get('entity_type.manager')
diff -u b/core/modules/media/tests/src/Kernel/BasicCreationTest.php b/core/modules/media/tests/src/Kernel/BasicCreationTest.php
--- b/core/modules/media/tests/src/Kernel/BasicCreationTest.php
+++ b/core/modules/media/tests/src/Kernel/BasicCreationTest.php
@@ -32,7 +32,7 @@
     // Source field is not set on the media source, but it should never
     // be created automatically when a config is being imported.
     $this->assertEquals(['source_field' => '', 'test_config_value' => 'Kakec'], $test_media_type->get('source_configuration'), 'Could not assure the correct media source configuration.');
-    $this->assertEquals([], $test_media_type->get('field_map'), 'Could not assure the correct field map.');
+    $this->assertEquals(['metadata_attribute' => 'field_attribute_config_test'], $test_media_type->get('field_map'), 'Could not assure the correct field map.');
   }
 
   /**
diff -u b/core/modules/media/tests/src/Kernel/MediaSourceTest.php b/core/modules/media/tests/src/Kernel/MediaSourceTest.php
--- b/core/modules/media/tests/src/Kernel/MediaSourceTest.php
+++ b/core/modules/media/tests/src/Kernel/MediaSourceTest.php
@@ -290,6 +290,7 @@
       $this->fail('Save was allowed without validation.');
     }
     catch (EntityStorageException $exception) {
+      $this->assertEquals('Entity validation was skipped.', $exception->getMessage(), 'Incorrect validation message.');
       $this->assertTrue(TRUE, 'Validation was enforced before save.');
     }
 
@@ -328,6 +329,7 @@
       $this->fail('Save was allowed without validation.');
     }
     catch (EntityStorageException $exception) {
+      $this->assertEquals('Entity validation was skipped.', $exception->getMessage(), 'Incorrect validation message.');
       $this->assertTrue(TRUE, 'Validation was enforced before save.');
     }
 
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/media/tests/src/Functional/MediaFunctionalTestCreateMediaTypeTrait.php
@@ -0,0 +1,67 @@
+<?php
+
+namespace Drupal\Tests\media\Functional;
+
+use Drupal\media\Entity\MediaType;
+
+/**
+ * Trait with helpers for Media functional tests.
+ */
+trait MediaFunctionalTestCreateMediaTypeTrait {
+
+  /**
+   * Creates a media type.
+   *
+   * @param array $values
+   *   The media type values.
+   * @param string $source
+   *   (optional) The media source plugin that is responsible for additional
+   *   logic related to this media type. Defaults to 'test'.
+   *
+   * @return \Drupal\media\MediaTypeInterface
+   *   A newly created media type.
+   */
+  protected function createMediaType(array $values = [], $source = 'test') {
+    if (empty($values['bundle'])) {
+      $id = strtolower($this->randomMachineName());
+    }
+    else {
+      $id = $values['bundle'];
+    }
+    $values += [
+      'id' => $id,
+      'label' => $id,
+      'source' => $source,
+      'source_configuration' => [],
+      'field_map' => [],
+      'new_revision' => FALSE,
+    ];
+
+    $media_type = MediaType::create($values);
+    $status = $media_type->save();
+
+    // @todo Rename to assertSame() when #1945040 is done.
+    // @see https://www.drupal.org/node/1945040
+    $this->assertIdentical(SAVED_NEW, $status, 'Media type was created successfully.');
+
+    // Ensure that the source field exists.
+    $source = $media_type->getSource();
+    $source_field = $source->getSourceFieldDefinition($media_type);
+    if (!$source_field) {
+      $source_field = $source->createSourceField($media_type);
+      /** @var \Drupal\field\FieldStorageConfigInterface $storage */
+      $storage = $source_field->getFieldStorageDefinition();
+      $storage->setLocked(TRUE)->save();
+      $source_field->save();
+
+      $media_type
+        ->set('source_configuration', [
+          'source_field' => $source_field->getName(),
+        ])
+        ->save();
+    }
+
+    return $media_type;
+  }
+
+}