diff --git a/core/tests/Drupal/Tests/Core/DrupalTest.php b/core/tests/Drupal/Tests/Core/DrupalTest.php
index 16a4e42..2f4da4e 100644
--- a/core/tests/Drupal/Tests/Core/DrupalTest.php
+++ b/core/tests/Drupal/Tests/Core/DrupalTest.php
@@ -320,7 +320,7 @@ public function testLinkGenerator() {
   }
 
   /**
-   * Tests the _l() method.
+   * Tests the l() method.
    *
    * @covers ::l
    * @see \Drupal\Core\Utility\LinkGeneratorInterface::generate()
diff --git a/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php b/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
index 71d2227..8c3a0f8 100644
--- a/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
@@ -295,9 +295,8 @@ public function testCustomStorage() {
   public function testDefaultValueCallback() {
     $definition = BaseFieldDefinition::create($this->fieldType);
     $callback = get_class($this) . '::mockDefaultValueCallback';
-    $this->assertInstanceOf('Drupal\Core\Field\BaseFieldDefinition',
-      $definition->setDefaultValueCallback($callback)
-    );
+    // setDefaultValueCallback returns $this.
+    $this->assertSame($definition, $definition->setDefaultValueCallback($callback));
   }
 
   /**
@@ -308,7 +307,8 @@ public function testDefaultValueCallback() {
    */
   public function testInvalidDefaultValueCallback() {
     $definition = BaseFieldDefinition::create($this->fieldType);
-    $this->assertInstanceOf('Drupal\Core\Field\BaseFieldDefinition',
+    // setDefaultValueCallback returns $this.
+    $this->assertSame($definition,
       $definition->setDefaultValueCallback([get_class($this), 'mockDefaultValueCallback'])
     );
   }
@@ -320,9 +320,8 @@ public function testInvalidDefaultValueCallback() {
    */
   public function testNullDefaultValueCallback() {
     $definition = BaseFieldDefinition::create($this->fieldType);
-    $this->assertInstanceOf('Drupal\Core\Field\BaseFieldDefinition',
-      $definition->setDefaultValueCallback(NULL)
-    );
+    // setDefaultValueCallback returns $this.
+    $this->assertSame($definition, $definition->setDefaultValueCallback(NULL));
   }
 
   /**