diff --git a/core/modules/layout/layout.module b/core/modules/layout/layout.module
index 5483699..5f034bd 100644
--- a/core/modules/layout/layout.module
+++ b/core/modules/layout/layout.module
@@ -16,21 +16,6 @@ function layout_manager() {
 }
 
 /**
- * Load a DisplayInterface object.
- *
- * This function exists solely for IDE typehinting purposes.
- *
- * @param        $name
- * @param string $type
- *
- * @return \Drupal\layout\Config\DisplayInterface
- *   The requested Display object.
- */
-function display_load($name, $type = 'display') {
-  return entity_load($type, $name);
-}
-
-/**
  * Implements hook_theme().
  *
  * Expose all layouts as theme items, so themes can override layout markup.
@@ -63,7 +48,6 @@ function layout_entity_info() {
       'fieldable' => FALSE,
       'entity keys' => array(
         'id' => 'id',
-        'label' => 'label', // @todo may not need this if internal-only (?)
         'uuid' => 'uuid',
       ),
     ),
@@ -75,7 +59,6 @@ function layout_entity_info() {
       'fieldable' => FALSE,
       'entity keys' => array(
         'id' => 'id',
-        'label' => 'label', // @todo may not need this if internal-only (?)
         'uuid' => 'uuid',
       ),
     )
diff --git a/core/modules/layout/lib/Drupal/layout/Config/BoundDisplayInterface.php b/core/modules/layout/lib/Drupal/layout/Config/BoundDisplayInterface.php
new file mode 100644
index 0000000..049d5ef
--- /dev/null
+++ b/core/modules/layout/lib/Drupal/layout/Config/BoundDisplayInterface.php
@@ -0,0 +1,75 @@
+<?php
+/**
+ * @file
+ * Definition of Drupal\layout\Config\BoundDisplayInterface
+ */
+
+namespace Drupal\layout\Config;
+
+use Drupal\layout\Plugin\LayoutInterface;
+
+interface BoundDisplayInterface extends DisplayInterface {
+
+  /**
+   * Set the layout plugin to be used by this display.
+   *
+   * @param string $plugin_id
+   *   The plugin id of the desired layout plugin.
+   */
+  public function setLayout($plugin_id);
+
+  /**
+   * Returns an indexed array of block config names, sorted by the order in
+   * which they should appear in the region.
+   *
+   * @param string $region
+   *   The region from which to return the set of blocks.
+   *
+   * @return array
+   */
+  public function getSortedBlocksByRegion($region);
+
+  /**
+   * Returns an array of arrays, keyed by region name and containing the
+   * same data as that which is returned by
+   * @see DisplayInterface::getSortedBlocksByRegion().
+   *
+   * @return mixed
+   */
+  public function getAllSortedBlocks();
+
+  /**
+   * Returns the layout plugin instance to be used with this display.
+   *
+   * @return \Drupal\layout\Plugin\LayoutInterface
+   */
+  public function getLayoutPluginInstance();
+
+  /**
+   * Perform block remapping per mapBlocksToLayout(), but mutate this object
+   * with the remapping results instead of returning them.
+   *
+   * @see \Drupal\layout\Config\DisplayBase::mapBlocksToLayout()
+   *
+   * @param \Drupal\layout\Plugin\LayoutInterface $layout
+   */
+  public function remapToLayout(LayoutInterface $layout);
+
+  /**
+   * Returns an UnboundDisplay by stripping out the layout and region-specific
+   * bindings on this object.
+   *
+   * @param string $id
+   *   The id that will be used to uniquely identify the created UnboundDisplay.
+   *   It will be appended to the config prefix for Displays ("display.unbound",
+   *   unless altered) to form the new Display's config address.
+   *
+   * @param string $entity_type
+   *   The type of entity to create. Must resolve to a class implementing
+   *   UnboundDisplayInterface.
+   *
+   * @return \Drupal\layout\Config\UnboundDisplayInterface
+   *   The newly-created UnboundDisplay.
+   */
+  public function generateUnboundDisplay($id, $entity_type = 'unbound_display');
+}
diff --git a/core/modules/layout/lib/Drupal/layout/Config/Display.php b/core/modules/layout/lib/Drupal/layout/Config/Display.php
index 8297900..26e948f 100644
--- a/core/modules/layout/lib/Drupal/layout/Config/Display.php
+++ b/core/modules/layout/lib/Drupal/layout/Config/Display.php
@@ -13,16 +13,103 @@
  * Configuration encapsulator that provides all the data needed by block-driven
  * controllers to render a page.
  */
-class Display extends DisplayBase {
+class Display extends DisplayBase implements BoundDisplayInterface {
+  /**
+   * An two-level array expressing block ordering within regions.
+   *
+   * The outer array is associative, keyed on region name. Each inner array is
+   * indexed, with the config address of a block as values and sorted according
+   * to order in which those blocks should appear in that region.
+   *
+   * This property is not stored statically in config, but is derived at runtime
+   * by DisplayBase::sortBlocks(). It is not stored statically because that
+   * would make using weights for ordering more difficult, and weights make
+   * external mass manipulation of displays much easier.
+   *
+   * @var array
+   */
+  protected $blocksInRegions;
+
+  /**
+   * The layout plugin instance being used to serve this page.
+   *
+   * @var \Drupal\layout\Plugin\LayoutInterface
+   */
+  protected $layoutPlugin;
 
-  public function __construct(array $values, $entity_type) {
-    // Forcibly restrict this from ever being built as a different entity type.
-    parent::__construct($values, 'display');
+  /**
+   * The name of the layout plugin to use.
+   *
+   * @var string
+   */
+  public $layout;
+
+  /**
+   * An array of settings to be coupled with the layout plugin to create a
+   * layout plugin instance.
+   *
+   * @var array
+   *
+   * @todo we might possibly want to separate this into its own config object
+   */
+  public $layoutSettings = array();
+
+  /**
+   * Implements DisplayInterface::getSortedBlocksByRegion().
+   *
+   * @param string $region
+   *
+   * @return array
+   * @throws \Exception
+   */
+  public function getSortedBlocksByRegion($region) {
+    if ($this->blocksInRegions === NULL) {
+      $this->sortBlocks();
+    }
+
+    if (!isset($this->blocksInRegions[$region])) {
+      throw new \Exception(sprintf("Region %region does not exist in layout %layout", array('%region' => $region, '%layout' => $this->getLayoutPluginInstance()->name)), E_RECOVERABLE_ERROR);
+    }
+
+    return $this->blocksInRegions[$region];
   }
 
-  public function setMainContent($callback, array $args = array()) {
-    // @todo need to wrap the callback up in a passthru block
-    // @todo consider throwing an exception if this display instance doesn't appear to support main content
+  /**
+   * Implements DisplayInterface::getAllSortedBlocks().
+   *
+   * @return array|mixed
+   */
+  public function getAllSortedBlocks() {
+    if ($this->blocksInRegions === NULL) {
+      $this->sortBlocks();
+    }
+
+    return $this->blocksInRegions;
+  }
+
+  /**
+   * Transform the stored blockConfig into a sorted, region-oriented array.
+   */
+  protected function sortBlocks() {
+    $layout_instance = $this->getLayoutPluginInstance();
+    if ($this->layout !== $layout_instance->getPluginId()) {
+      $block_config = $this->mapBlocksToLayout($layout_instance);
+    }
+    else {
+      $block_config = $this->blockInfo;
+    }
+
+    $this->blocksInRegions = array();
+
+    $regions = array_fill_keys(array_keys($layout_instance->getRegions()), array());
+    foreach ($block_config as $config_name => $info) {
+      $regions[$info['region']][$config_name] = $info;
+    }
+
+    foreach ($regions as $region_name => &$blocks) {
+      uasort($blocks, 'drupal_sort_weight');
+      $this->blocksInRegions[$region_name] = array_keys($blocks);
+    }
   }
 
   /**
@@ -52,18 +139,11 @@ public function setLayout($plugin_id) {
   }
 
   /**
-   * Returns an UnboundDisplay by stripping out the layout and region-specific
-   * bindings on this object.
-   *
-   * @param string $id
-   *   The id that will be used to uniquely identify the created UnboundDisplay.
-   *   It will be appended to the config prefix for Displays ("display.unbound",
-   *   unless altered) to form the new Display's config address.
+   * Implements BoundDisplayInterface::generateUnboundDisplay().
    *
-   * @return \Drupal\layout\Config\UnboundDisplay
-   *   The newly-created UnboundDisplay.
+   * @throws \Exception
    */
-  public function generateUnboundDisplay($id) {
+  public function generateUnboundDisplay($id, $entity_type = 'unbound_display') {
     $block_info = $this->getAllBlockInfo();
     foreach ($block_info as &$info) {
       unset ($info['region']);
@@ -71,11 +151,15 @@ public function generateUnboundDisplay($id) {
 
     $values = array(
       'blockInfo' => $block_info,
-      'staticData' => $this->staticData, // @todo this could create portability problems
       'id' => $id,
     );
 
-    return entity_create('unbound_display', $values);
+    $entity = entity_create($entity_type, $values);
+    if (!$entity instanceof UnboundDisplayInterface) {
+      throw new \Exception(sprintf('Attempted to create an unbound display using an invalid entity type.'), E_RECOVERABLE_ERROR);
+    }
+
+    return $entity;
   }
 
   public function getLayoutPluginInstance() {
diff --git a/core/modules/layout/lib/Drupal/layout/Config/DisplayBase.php b/core/modules/layout/lib/Drupal/layout/Config/DisplayBase.php
index c7b65bd..95c07bb 100644
--- a/core/modules/layout/lib/Drupal/layout/Config/DisplayBase.php
+++ b/core/modules/layout/lib/Drupal/layout/Config/DisplayBase.php
@@ -27,14 +27,6 @@
   public $id;
 
   /**
-   * The human-readable label of this display.
-   * @todo we probably don't need/want to have this - but is it safe to remove?
-   *
-   * @var string
-   */
-  public $label;
-
-  /**
    * The UUID identifying a specific display object.
    *
    * @var string
@@ -42,43 +34,6 @@
   public $uuid;
 
   /**
-   * The layout plugin instance being used to serve this page.
-   *
-   * @var \Drupal\layout\Plugin\LayoutInterface
-   */
-  protected $layoutPlugin;
-
-  /**
-   * The name of the layout plugin to use.
-   *
-   * @var string
-   */
-  public $layout;
-
-  /**
-   * An array of settings to be coupled with the layout plugin to create a
-   * layout plugin instance.
-   *
-   * @var array
-   *
-   * @todo we might possibly want to separate this into its own config object
-   */
-  public $layoutSettings = array();
-
-  /**
-   * Storage for data sources that have been statically assigned - that is, not
-   * derived in some way from the Request.
-   *
-   * The array is keyed on the name of a data source, and the values are getters
-   * that are able to retrieve the appropriate data.
-   *
-   * @todo define how the getters work.
-   *
-   * @var array
-   */
-  public $staticData = array();
-
-  /**
    * Contains all block configuration.
    *
    * There are two levels to the configuration contained herein: display-level
@@ -125,76 +80,24 @@
    */
   protected $blockInfo = array();
 
-  protected $blocksInRegions;
-
   /**
-   * {@inheritdoc}
-   *
-   * @todo this is super hacky right now, and we need to determine how we do this.
+   * Implements DisplayInterface::getAllBlockInfo().
    *
-   * @return bool
+   * @return array
    */
-  public function hasMainContent() {
-    $info = $this->getAllBlockInfo();
-    return (isset($info['maincontent']));
-  }
-
   public function getAllBlockInfo() {
     return $this->blockInfo;
   }
 
-  public function getSortedBlocksByRegion($region = '') {
-    if ($this->blocksInRegions === NULL) {
-      $this->sortBlocks();
-    }
-
-    if (!isset($this->blocksInRegions[$region])) {
-      throw new \Exception(sprintf("Region %region does not exist in layout %layout", array('%region' => $region, '%layout' => $this->getLayoutPluginInstance()->name)), E_RECOVERABLE_ERROR);
-    }
-
-    return $this->blocksInRegions[$region];
-  }
-
-  public function getAllSortedBlocks() {
-    if ($this->blocksInRegions === NULL) {
-      $this->sortBlocks();
-    }
-
-    return $this->blocksInRegions;
-  }
-
-  /**
-   * @param $info
-   */
-  public function setBlockInfo($info) {
-    $this->blockInfo = $info;
-  }
-
   /**
-   * Transform the stored blockConfig into a sorted, region-oriented array.
+   * Implements DisplayInterface::mapBlocksToLayout().
+   *
+   * @todo this logic ought not be tightly coupled to this class.
+   *
+   * @param \Drupal\layout\Plugin\LayoutInterface $layout
+   *
+   * @return array
    */
-  protected function sortBlocks() {
-    $layout_instance = $this->getLayoutPluginInstance();
-    if ($this->layout !== $layout_instance->getPluginId()) {
-      $block_config = $this->mapBlocksToLayout($layout_instance);
-    }
-    else {
-      $block_config = $this->blockInfo;
-    }
-
-    $this->blocksInRegions = array();
-
-    $regions = array_fill_keys(array_keys($layout_instance->getRegions()), array());
-    foreach ($block_config as $config_name => $info) {
-      $regions[$info['region']][$config_name] = $info;
-    }
-
-    foreach ($regions as $region_name => &$blocks) {
-      uasort($blocks, 'drupal_sort_weight');
-      $this->blocksInRegions[$region_name] = array_keys($blocks);
-    }
-  }
-
   public function mapBlocksToLayout(LayoutInterface $layout) {
     $types = array();
 
@@ -212,7 +115,6 @@ public function mapBlocksToLayout(LayoutInterface $layout) {
       }
       // Then, try to remap using region types.
       else if (!empty($types[$info['region-type']])) {
-        // @todo this logic means we only EVER assign to the first region of a type. ick.
         $info['region'] = reset($types[$info['region-type']]);
       }
       // Finally, fall back to dumping everything in the layout's first region.
diff --git a/core/modules/layout/lib/Drupal/layout/Config/DisplayInterface.php b/core/modules/layout/lib/Drupal/layout/Config/DisplayInterface.php
index 1b38676..1337077 100644
--- a/core/modules/layout/lib/Drupal/layout/Config/DisplayInterface.php
+++ b/core/modules/layout/lib/Drupal/layout/Config/DisplayInterface.php
@@ -11,58 +11,6 @@
 interface DisplayInterface {
 
   /**
-   * Introspects the contained config to determine whether or not this Display
-   * supports the 'main content' passthrough.
-   *
-   * @return bool
-   */
-  public function hasMainContent();
-
-  /**
-   * Sets the controller that should be used to serve the main page content.
-   *
-   * "Main page content" is analogous to the callback specified in
-   * 'page callback' in Drupal 6 and 7. In a blocks-driven world, such direct
-   * callbacks run a bit against the grain. However, the simplicity of
-   * implementing and understanding it is so beneficial to developer experience
-   * that we provide this 'main' content option, which simulates the old
-   * behavior by injecting a virtualized 'main' block that passes through
-   * to a specified callback.
-   *
-   * We normalize the main content block here in the configuration object so
-   * that various controllers consuming the display need not repeatedly
-   * implement this special handling for the main callback.
-   *
-   * @todo this is fairly specific to pages - maybe not best for the interface
-   *
-   * @param Callable $callback
-   *   Any form of callable.
-   * @param array $args
-   *   An array of arguments to pass to the callable.
-   */
-  public function setMainContent($callback, array $args = array());
-
-  /**
-   * Returns an indexed array of block config names, sorted by the order in
-   * which they should appear in the region.
-   *    *
-   * @param string $region
-   *   The region from which to return the set of blocks.
-   *
-   * @return array
-   */
-  public function getSortedBlocksByRegion($region = '');
-
-  /**
-   * Returns an array of arrays, keyed by region name and containing the
-   * same data as that which is returned by
-   * @see DisplayInterface::getSortedBlocksByRegion().
-   *
-   * @return mixed
-   */
-  public function getAllSortedBlocks();
-
-  /**
    * Returns the config info about all blocks on this display.
    *
    * There are two levels of configuration that are being captured here: the
@@ -88,11 +36,4 @@ public function getAllBlockInfo();
    *   is returned by DisplayInterface::getAllBlockInfo().
    */
   public function mapBlocksToLayout(LayoutInterface $layout);
-
-  /**
-   * Returns the layout plugin instance to be used with this display.
-   *
-   * @return \Drupal\layout\Plugin\LayoutInterface
-   */
-  public function getLayoutPluginInstance();
 }
diff --git a/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplay.php b/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplay.php
index 27eda8f..7a066af 100644
--- a/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplay.php
+++ b/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplay.php
@@ -16,48 +16,26 @@
  * Unbound displays contain blocks that are not 'bound' to a specific layout,
  * and their contained blocks are mapped only to region types, not real regions.
  */
-class UnboundDisplay extends DisplayBase {
-
-  public function __construct(array $values, $entity_type) {
-    // Forcibly restrict this from ever being built as a different entity type.
-    parent::__construct($values, 'display');
-  }
-
-  public function setMainContent($callback, array $args = array()) {
-    throw new \Exception('Cannot set the main content passthrough block an an unbound display.', E_RECOVERABLE_ERROR);
-  }
+class UnboundDisplay extends DisplayBase implements UnboundDisplayInterface {
 
   /**
-   * Bind this UnboundDisplay to a particular display.
-   *
-   * This will DisplayInterface::mapBlocksToLayout() using the provided layout,
-   * then create and return a new Display object with the output. This is just
-   * a factory - calling code is responsible for saving the
+   * Implements UnboundDisplayInterface::generateDisplay().
    *
-   * @param \Drupal\layout\Plugin\LayoutInterface $layout
-   *   The layout plugin to which this config object should be bound.
-   *
-   * @param string $id
-   *   The id that will be used to uniquely identify the created Display. It
-   *   will be appended to the config prefix for Displays ("display", unless
-   *   altered) to form the new Display's config address.
-   *
-   * @return \Drupal\layout\Config\Display
-   *   A Display object that has had the data from this config object mapped to
-   *   the provided layout plugin.
+   * @throws \Exception
    */
-  public function generateDisplay(LayoutInterface $layout, $id) {
+  public function generateDisplay(LayoutInterface $layout, $id, $entity_type = 'display') {
     $values = array(
       'layout' => $layout->getPluginId(),
       'blockInfo' => $this->mapBlocksToLayout($layout),
-      'staticData' => $this->staticData, // @todo this could create portability problems
       'id' => $id,
     );
 
-    return entity_create('display', $values);
-  }
+    $entity = entity_create($entity_type, $values);
+
+    if (!$entity instanceof BoundDisplayInterface) {
+      throw new \Exception(sprintf('Attempted to bind an unbound display but provided an invalid entity type.'), E_RECOVERABLE_ERROR);
+    }
 
-  public function getLayoutPluginInstance() {
-    throw new \Exception('Cannot get a layout plugin from an unbound display; by definition, they are not bound to a layout.', E_RECOVERABLE_ERROR);
+    return $entity;
   }
 }
diff --git a/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplayInterface.php b/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplayInterface.php
new file mode 100644
index 0000000..9549788
--- /dev/null
+++ b/core/modules/layout/lib/Drupal/layout/Config/UnboundDisplayInterface.php
@@ -0,0 +1,36 @@
+<?php
+/**
+ * @file
+ * Definition of Drupal\layout\Config\UnboundDisplayInterface
+ */
+
+namespace Drupal\layout\Config;
+
+use Drupal\layout\Plugin\LayoutInterface;
+
+interface UnboundDisplayInterface extends DisplayInterface {
+  /**
+   * Bind this UnboundDisplay to a particular display.
+   *
+   * This will DisplayInterface::mapBlocksToLayout() using the provided layout,
+   * then create and return a new Display object with the output. This is just
+   * a factory - calling code is responsible for saving the
+   *
+   * @param \Drupal\layout\Plugin\LayoutInterface $layout
+   *   The layout plugin to which this config object should be bound.
+   *
+   * @param string $id
+   *   The id that will be used to uniquely identify the created Display. It
+   *   will be appended to the config prefix for Displays ("display", unless
+   *   altered) to form the new Display's config address.
+   *
+   * @param string $entity_type
+   *   The type of entity to create. Must resolve to a class implementing
+   *   BoundDisplayInterface.
+   *
+   * @return \Drupal\layout\Config\Display
+   *   A Display object that has had the data from this config object mapped to
+   *   the provided layout plugin.
+   */
+  public function generateDisplay(LayoutInterface $layout, $id, $entity_type = 'display');
+}
diff --git a/core/modules/layout/lib/Drupal/layout/Tests/DisplayInternalLogicTest.php b/core/modules/layout/lib/Drupal/layout/Tests/DisplayInternalLogicTest.php
index 4c83fa5..d1b2f6b 100644
--- a/core/modules/layout/lib/Drupal/layout/Tests/DisplayInternalLogicTest.php
+++ b/core/modules/layout/lib/Drupal/layout/Tests/DisplayInternalLogicTest.php
@@ -56,9 +56,9 @@ public static function getInfo() {
 
   public function setUp() {
     parent::setUp();
-    $this->twocol = display_load('test_twocol');
-    $this->onecol = display_load('test_onecol');
-    $this->unbound = display_load('test_unbound_display', 'unbound_display');
+    $this->twocol = entity_load('display', 'test_twocol');
+    $this->onecol = entity_load('display', 'test_onecol');
+    $this->unbound = entity_load('unbound_display', 'test_unbound_display');
   }
 
   /**
@@ -69,12 +69,12 @@ public function testBlockSorting() {
     $left = $this->twocol->getSortedBlocksByRegion('left');
     $this->assertEqual(count($left), 2, 'Two blocks found in left region.');
     list($first, $second) = $left;
-    $this->assertEqual($first, 'plugin.core.block.navigation_instance2', 'navigation_instance2 block instance is first in the left region.');
-    $this->assertEqual($second, 'plugin.core.block.main_block', 'main_block block instance is second in the left region.');
+    $this->assertIdentical($first, 'plugin.core.block.test_navigation_instance2');
+    $this->assertIdentical($second, 'plugin.core.block.test_main_block');
 
     $right = $this->twocol->getSortedBlocksByRegion('right');
     $this->assertEqual(count($right), 1, 'One block found in right region.');
-    $this->assertEqual(reset($right), 'plugin.core.block.navigation_instance', 'navigation_instance block instance is the only block in the right region.');
+    $this->assertIdentical(reset($right), 'plugin.core.block.test_navigation_instance', 'test_navigation_instance block instance is the only block in the right region.');
 
     $all = $this->twocol->getAllSortedBlocks();
     $this->assertEqual(count($all), 2, 'Block sorting produces exactly two regions.');
@@ -97,9 +97,9 @@ public function testBlockMapping() {
     list($first, $second, $third) = $middle;
 
     // @todo the determining factors for which of the nav instances comes first is twisty. improve it.
-    $this->assertEqual($first, 'plugin.core.block.navigation_instance2', 'navigation_instance2 block instance is first in the only region after twocol to onecol remapping.');
-    $this->assertEqual($second, 'plugin.core.block.navigation_instance', 'navigation_instance block instance is second in the only region after twocol to onecol remapping.');
-    $this->assertEqual($third, 'plugin.core.block.main_block', 'main_block block instance is third and last in the only region after twocol to onecol remapping.');
+    $this->assertIdentical($first, 'plugin.core.block.test_navigation_instance2');
+    $this->assertIdentical($second, 'plugin.core.block.test_navigation_instance');
+    $this->assertIdentical($third, 'plugin.core.block.test_main_block');
 
     // Now, remap from the onecol to twocol.
     $one_to_two = clone($this->onecol);
@@ -107,8 +107,8 @@ public function testBlockMapping() {
 
     $this->assertEqual(count($one_to_two->getAllSortedBlocks()), 2, 'getAllSortedBlocks() returns two regions even though one is empty after onecol to twocol remapping.');
     list($first, $second) = $one_to_two->getSortedBlocksByRegion('left');
-    $this->assertEqual($first, 'plugin.core.block.navigation_instance', 'navigation_instance block instance is first in the left region after onecol to twocol remapping.');
-    $this->assertEqual($second, 'plugin.core.block.main_block', 'main_block block instance is second in the left region after onecol to twocol remapping.');
+    $this->assertIdentical($first, 'plugin.core.block.test_navigation_instance');
+    $this->assertIdentical($second, 'plugin.core.block.test_main_block');
     // Make sure we have an empty right region - no surprises!
     $this->assertIdentical($one_to_two->getSortedBlocksByRegion('right'), array(), 'Region with no blocks comes back from getSortedBlocksByRegion() as an empty array.');
 
@@ -117,8 +117,8 @@ public function testBlockMapping() {
     $this->assertTrue($unbound_to_twocol instanceof Display, 'Binding the unbound display successfully created a Display object');
     $left = $unbound_to_twocol->getSortedBlocksByRegion('left');
     list($first, $second) = $left;
-    $this->assertEqual($first, 'plugin.core.block.main_block', 'main_block block instance is first in the left region after generating a display by binding the unbound test to twocol.');
-    $this->assertEqual($second, 'plugin.core.block.navigation_instance2', 'navigation_instance2 block instance ended up in left region as a fallback when generating a display by binding the unbound test to twocol.');
+    $this->assertIdentical($first, 'plugin.core.block.test_main_block');
+    $this->assertIdentical($second, 'plugin.core.block.test_navigation_instance2');
 
     // Finally, generate an unbound display from the twocol display.
     $twocol_to_unbound = $this->twocol->generateUnboundDisplay('twocol_to_unbound');
@@ -130,8 +130,8 @@ public function testBlockMapping() {
       $this->assertTrue(empty($info['region']), sprintf('Block info for block %address has no region associated with it.', array('%address' => $address)));
     }
 
-    $this->assertEqual($blocks_info['plugin.core.block.main_block']['region-type'], 'content', 'main_block is mapped to region type "content".');
-    $this->assertEqual($blocks_info['plugin.core.block.navigation_instance']['region-type'], 'aside', 'navigation_instance is mapped to region type "aside".');
-    $this->assertEqual($blocks_info['plugin.core.block.navigation_instance2']['region-type'], 'content', 'navigation_instance2 is mapped to region type "content".');
+    $this->assertIdentical($blocks_info['plugin.core.block.test_main_block']['region-type'], 'content');
+    $this->assertIdentical($blocks_info['plugin.core.block.test_navigation_instance']['region-type'], 'aside');
+    $this->assertIdentical($blocks_info['plugin.core.block.test_navigation_instance2']['region-type'], 'content');
   }
 }
diff --git a/core/modules/layout/tests/config/display.test_onecol.yml b/core/modules/layout/tests/config/display.test_onecol.yml
index f1176bf..dda0342 100644
--- a/core/modules/layout/tests/config/display.test_onecol.yml
+++ b/core/modules/layout/tests/config/display.test_onecol.yml
@@ -4,11 +4,11 @@ layout: static_layout:layout_test__one-col
 layoutSettings: { }
 staticData: { }
 blockInfo:
-  plugin.core.block.main_block:
+  plugin.core.block.test_main_block:
     region: middle
     region-type: content
     weight: 100
-  plugin.core.block.navigation_instance:
+  plugin.core.block.test_navigation_instance:
     region: middle
     region-type: content
     weight: -100
diff --git a/core/modules/layout/tests/config/display.test_twocol.yml b/core/modules/layout/tests/config/display.test_twocol.yml
index 431fa7a..fefe355 100644
--- a/core/modules/layout/tests/config/display.test_twocol.yml
+++ b/core/modules/layout/tests/config/display.test_twocol.yml
@@ -4,15 +4,15 @@ layout: static_layout:layout_test_theme__two-col
 layoutSettings: { }
 staticData: { }
 blockInfo:
-  plugin.core.block.main_block:
+  plugin.core.block.test_main_block:
     region: left
     region-type: content
     weight: 100
-  plugin.core.block.navigation_instance:
+  plugin.core.block.test_navigation_instance:
     region: right
     region-type: aside
     weight: -100
-  plugin.core.block.navigation_instance2:
+  plugin.core.block.test_navigation_instance2:
     region: left
     region-type: content
     weight: -100
\ No newline at end of file
diff --git a/core/modules/layout/tests/config/display.unbound.test_unbound_display.yml b/core/modules/layout/tests/config/display.unbound.test_unbound_display.yml
index e51a56d..db8c8fc 100644
--- a/core/modules/layout/tests/config/display.unbound.test_unbound_display.yml
+++ b/core/modules/layout/tests/config/display.unbound.test_unbound_display.yml
@@ -3,12 +3,12 @@ label: Unbound display test
 layoutSettings: { }
 staticData: { }
 blockInfo:
-  plugin.core.block.main_block:
+  plugin.core.block.test_main_block:
     region-type: content
     weight: -100
-  plugin.core.block.navigation_instance:
+  plugin.core.block.test_navigation_instance:
     region-type: aside
     weight: -100
-  plugin.core.block.navigation_instance2:
+  plugin.core.block.test_navigation_instance2:
     region-type: nav
     weight: 0
\ No newline at end of file
diff --git a/core/modules/layout/tests/config/plugin.core.block.main_block.yml b/core/modules/layout/tests/config/plugin.core.block.main_block.yml
deleted file mode 100644
index de31170..0000000
--- a/core/modules/layout/tests/config/plugin.core.block.main_block.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-id: system_main_block
-status: '1'
-cache: '-1'
-visibility:
-  path:
-    visibility: '0'
-    pages: ''
-  role:
-    roles: {  }
-  node_type:
-    types:
-      article: '0'
-      page: '0'
-  visibility__active_tab: edit-visibility-path
-subject: 'main content'
-module: system
-region: content
-weight: '0'
diff --git a/core/modules/layout/tests/config/plugin.core.block.navigation_instance.yml b/core/modules/layout/tests/config/plugin.core.block.navigation_instance.yml
deleted file mode 100644
index c833f42..0000000
--- a/core/modules/layout/tests/config/plugin.core.block.navigation_instance.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-id: 'system_menu_block:navigation'
-status: '1'
-cache: '-1'
-visibility:
-  path:
-    visibility: '0'
-    pages: ''
-  role:
-    roles: {  }
-  node_type:
-    types:
-      article: '0'
-      page: '0'
-  visibility__active_tab: edit-visibility-path
-subject: Navigation
-module: system
-region: sidebar_first
-weight: '0'
diff --git a/core/modules/layout/tests/config/plugin.core.block.navigation_instance2.yml b/core/modules/layout/tests/config/plugin.core.block.navigation_instance2.yml
deleted file mode 100644
index c833f42..0000000
--- a/core/modules/layout/tests/config/plugin.core.block.navigation_instance2.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-id: 'system_menu_block:navigation'
-status: '1'
-cache: '-1'
-visibility:
-  path:
-    visibility: '0'
-    pages: ''
-  role:
-    roles: {  }
-  node_type:
-    types:
-      article: '0'
-      page: '0'
-  visibility__active_tab: edit-visibility-path
-subject: Navigation
-module: system
-region: sidebar_first
-weight: '0'
diff --git a/core/modules/layout/tests/config/plugin.core.block.test_main_block.yml b/core/modules/layout/tests/config/plugin.core.block.test_main_block.yml
new file mode 100644
index 0000000..de31170
--- /dev/null
+++ b/core/modules/layout/tests/config/plugin.core.block.test_main_block.yml
@@ -0,0 +1,18 @@
+id: system_main_block
+status: '1'
+cache: '-1'
+visibility:
+  path:
+    visibility: '0'
+    pages: ''
+  role:
+    roles: {  }
+  node_type:
+    types:
+      article: '0'
+      page: '0'
+  visibility__active_tab: edit-visibility-path
+subject: 'main content'
+module: system
+region: content
+weight: '0'
diff --git a/core/modules/layout/tests/config/plugin.core.block.test_navigation_instance.yml b/core/modules/layout/tests/config/plugin.core.block.test_navigation_instance.yml
new file mode 100644
index 0000000..c833f42
--- /dev/null
+++ b/core/modules/layout/tests/config/plugin.core.block.test_navigation_instance.yml
@@ -0,0 +1,18 @@
+id: 'system_menu_block:navigation'
+status: '1'
+cache: '-1'
+visibility:
+  path:
+    visibility: '0'
+    pages: ''
+  role:
+    roles: {  }
+  node_type:
+    types:
+      article: '0'
+      page: '0'
+  visibility__active_tab: edit-visibility-path
+subject: Navigation
+module: system
+region: sidebar_first
+weight: '0'
diff --git a/core/modules/layout/tests/config/plugin.core.block.test_navigation_instance2.yml b/core/modules/layout/tests/config/plugin.core.block.test_navigation_instance2.yml
new file mode 100644
index 0000000..c833f42
--- /dev/null
+++ b/core/modules/layout/tests/config/plugin.core.block.test_navigation_instance2.yml
@@ -0,0 +1,18 @@
+id: 'system_menu_block:navigation'
+status: '1'
+cache: '-1'
+visibility:
+  path:
+    visibility: '0'
+    pages: ''
+  role:
+    roles: {  }
+  node_type:
+    types:
+      article: '0'
+      page: '0'
+  visibility__active_tab: edit-visibility-path
+subject: Navigation
+module: system
+region: sidebar_first
+weight: '0'
diff --git a/core/modules/layout/tests/layout_test.module b/core/modules/layout/tests/layout_test.module
index 687f0bd..07e6d3c 100644
--- a/core/modules/layout/tests/layout_test.module
+++ b/core/modules/layout/tests/layout_test.module
@@ -26,9 +26,9 @@ function layout_test_page() {
   global $theme;
   $theme = 'layout_test_theme';
   theme_enable(array($theme));
-  $display = display_load('test_twocol');
+  $display = entity_load('display', 'test_twocol');
   $layout = $display->getLayoutPluginInstance();
-  // @fixme this implementation ignores blocks completely, so is inherently incomplete.
+  // @todo this implementation ignores blocks completely, so is inherently incomplete.
   return $layout->renderLayout();
 }