Index: /trunk/tests/phpunit/tests/functions/maybeSerialize.php
===================================================================
--- /trunk/tests/phpunit/tests/functions/maybeSerialize.php	(revision 63160)
+++ /trunk/tests/phpunit/tests/functions/maybeSerialize.php	(revision 63161)
@@ -223,5 +223,5 @@
 			$callback_value = $property->getValue( $new_value );
 
-			$this->assertSame( null, $callback_value );
+			$this->assertNull( $callback_value );
 		} else {
 			$this->assertSame( $value->count(), unserialize( $serialized )->count() );
Index: /trunk/tests/phpunit/tests/post/types.php
===================================================================
--- /trunk/tests/phpunit/tests/post/types.php	(revision 63160)
+++ /trunk/tests/phpunit/tests/post/types.php	(revision 63161)
@@ -627,5 +627,5 @@
 		remove_post_type_support( 'foo', 'autosave' );
 		$post_type_object = get_post_type_object( 'foo' );
-		$this->assertSame( null, $post_type_object->get_autosave_rest_controller(), 'Autosave controller should be removed.' );
+		$this->assertNull( $post_type_object->get_autosave_rest_controller(), 'Autosave controller should be removed.' );
 		_unregister_post_type( 'foo' );
 	}
Index: /trunk/tests/phpunit/tests/post/wpAfterInsertPost.php
===================================================================
--- /trunk/tests/phpunit/tests/post/wpAfterInsertPost.php	(revision 63160)
+++ /trunk/tests/phpunit/tests/post/wpAfterInsertPost.php	(revision 63161)
@@ -158,5 +158,5 @@
 		);
 
-		$this->assertSame( null, self::$passed_post_before_status );
+		$this->assertNull( self::$passed_post_before_status );
 		$this->assertSame( 'a new post', self::$passed_post_title );
 	}
@@ -198,5 +198,5 @@
 		rest_get_server()->dispatch( $request );
 
-		$this->assertSame( null, self::$passed_post_before_title );
+		$this->assertNull( self::$passed_post_before_title );
 		$this->assertSame( 'new title', self::$passed_post_title );
 	}
Index: /trunk/tests/phpunit/tests/rest-api/rest-settings-controller.php
===================================================================
--- /trunk/tests/phpunit/tests/rest-api/rest-settings-controller.php	(revision 63160)
+++ /trunk/tests/phpunit/tests/rest-api/rest-settings-controller.php	(revision 63161)
@@ -795,5 +795,5 @@
 		$this->assertSame( 'Title', $title['title'] );
 		$this->assertSame( 'Site title.', $title['description'] );
-		$this->assertSame( null, $title['default'] );
+		$this->assertNull( $title['default'] );
 	}
 }
Index: /trunk/tests/phpunit/tests/theme/wpGetBlockCssSelector.php
===================================================================
--- /trunk/tests/phpunit/tests/theme/wpGetBlockCssSelector.php	(revision 63160)
+++ /trunk/tests/phpunit/tests/theme/wpGetBlockCssSelector.php	(revision 63161)
@@ -132,5 +132,5 @@
 
 		$selector = wp_get_block_css_selector( $block_type, 'typography' );
-		$this->assertSame( null, $selector );
+		$this->assertNull( $selector );
 	}
 
@@ -206,5 +206,5 @@
 
 		$selector = wp_get_block_css_selector( $block_type, 'typography' );
-		$this->assertSame( null, $selector );
+		$this->assertNull( $selector );
 	}
 
@@ -263,5 +263,5 @@
 
 		$selector = wp_get_block_css_selector( $block_type, array( 'typography', 'fontSize' ) );
-		$this->assertSame( null, $selector );
+		$this->assertNull( $selector );
 	}
 
@@ -298,5 +298,5 @@
 			array( 'typography', 'fontSize' )
 		);
-		$this->assertSame( null, $selector );
+		$this->assertNull( $selector );
 	}
 
@@ -312,8 +312,8 @@
 
 		$selector = wp_get_block_css_selector( $block_type, array() );
-		$this->assertSame( null, $selector );
+		$this->assertNull( $selector );
 
 		$selector = wp_get_block_css_selector( $block_type, '' );
-		$this->assertSame( null, $selector );
+		$this->assertNull( $selector );
 	}