diff --git a/core/tests/Drupal/KernelTests/Core/Entity/EntityOriginalRevisionTest.php b/core/tests/Drupal/KernelTests/Core/Entity/EntityOriginalRevisionTest.php
index 138dbef..1694dad 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/EntityOriginalRevisionTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/EntityOriginalRevisionTest.php
@@ -29,21 +29,49 @@ protected function setUp() {
   }
 
   public function testPreviousProperty() {
+    // Create a basic EntityTestMulRev entity and save it.
     $entity = EntityTestMulRev::create();
     $entity->save();
 
+    // Load the created entity and create a new revision.
     $loaded = EntityTestMulRev::load($entity->id());
     $loaded->setNewRevision(TRUE);
+
+    // Before saving the original revision ID should be the same as the created
+    // entity, not the same as the loaded entity (which won't have a revision id
+    // yet).
+    $this->assertEquals($entity->getRevisionId(), $loaded->getOriginalRevisionId());
+    $this->assertNotEquals($loaded->getRevisionId(), $loaded->getOriginalRevisionId());
+    $this->assertTrue($loaded->getRevisionId() === NULL);
+
     $loaded->save();
 
+    // In hook_update the original revision id was stored in state. This should
+    // be the same as we had before calling $loaded->save().
     /** @var \Drupal\Core\Entity\ContentEntityInterface $loaded_original */
     $originalRevisionId = \Drupal::state()->get('entity_test.originalRevisionId');
     $this->assertEquals($entity->getRevisionId(), $originalRevisionId);
     $this->assertNotEquals($loaded->getRevisionId(), $originalRevisionId);
 
+    // The revision ID and original revision ID should be different for the two
+    // versions of the entity, but the same for a saved entity.
+    $this->assertNotEquals($loaded->getRevisionId(), $entity->getRevisionId());
+    $this->assertNotEquals($loaded->getOriginalRevisionId(), $entity->getOriginalRevisionId());
+    $this->assertEquals($entity->getRevisionId(), $entity->getOriginalRevisionId());
+    $this->assertEquals($loaded->getRevisionId(), $loaded->getOriginalRevisionId());
+
+    // Make a change to the loaded entity.
     $loaded->set('name', 'dublin');
+
+    // The revision id and original revision id should still be the same.
+    $this->assertEquals($loaded->getRevisionId(), $loaded->getOriginalRevisionId());
+
     $loaded->save();
+
+    // After saving the original revision id set in hook_update, and returned
+    // from the entity should be the same and the entity's revision id.
     $originalRevisionId2 = \Drupal::state()->get('entity_test.originalRevisionId');
     $this->assertEquals($loaded->getRevisionId(), $originalRevisionId2);
+    $this->assertEquals($loaded->getRevisionId(), $loaded->getOriginalRevisionId());
   }
 }