Index: tests/ajax/Response.php
===================================================================
--- tests/ajax/Response.php	(revision 0)
+++ tests/ajax/Response.php	(working copy)
@@ -0,0 +1,99 @@
+<?php
+
+/**
+ * Testing ajax response class
+ *
+ * @package    WordPress
+ * @subpackage UnitTests
+ * @since      3.5.0
+ * @group      ajax
+ */
+class Tests_Ajax_Response extends WP_UnitTestCase {
+
+	/**
+	 * Saved error reporting level
+	 * @var int
+	 */
+	protected $_error_level = 0;
+	
+	/**
+	 * Set up the test fixture.
+	 * Override wp_die(), pretend to be ajax, and suppres E_WARNINGs
+	 */
+	public function setUp() {
+		parent::setUp();
+
+		add_filter( 'wp_die_ajax_handler', array( $this, 'getDieHandler' ), 1, 1 );
+		if ( !defined( 'DOING_AJAX' ) )
+			define( 'DOING_AJAX', true );
+
+		// Suppress warnings from "Cannot modify header information - headers already sent by"
+		$this->_error_level = error_reporting();
+		error_reporting( $this->_error_level & ~E_WARNING );
+	}
+
+	/**
+	 * Tear down the test fixture.
+	 * Remove the wp_die() override, restore error reporting
+	 */
+	public function tearDown() {
+		parent::tearDown();
+		remove_filter( 'wp_die_ajax_handler', array( $this, 'getDieHandler' ), 1, 1 );
+		error_reporting( $this->_error_level );
+	}
+	
+	/**
+	 * Return our callback handler
+	 * @return callback
+	 */
+	public function getDieHandler() {
+		return array( $this, 'dieHandler' );
+	}
+
+	/**
+	 * Handler for wp_die()
+	 * Don't die, just continue on.
+	 * @param string $message
+	 */
+	public function dieHandler( $message ) {
+	}
+
+	/**
+	 * Test that charset in header matches blog_charset
+	 * Note:  headers_list doesn't work properly in CLI mode, fall back on
+	 * xdebug_get_headers if it's available
+	 * @ticket 19448
+	 */
+	public function test_response_charset_in_header() {
+
+		if ( !function_exists( 'xdebug_get_headers' ) ) {
+			$this->markTestSkipped( 'xdebug is required for this test' );
+		}
+		
+		// Generate an ajax response
+		ob_start();
+		$ajax_response = new WP_Ajax_Response();
+		$ajax_response->send();
+
+		// Check the header
+		$headers = xdebug_get_headers();
+		ob_end_clean();
+		$this->assertTrue( in_array( 'Content-Type: text/xml; charset=' . get_option( 'blog_charset' ), $headers ) );
+	}
+	
+	/**
+	 * Test that charset in the xml tag matches blog_charset
+	 * @ticket 19448
+	 */
+	public function test_response_charset_in_xml() {
+		
+		// Generate an ajax response
+		ob_start();
+		$ajax_response = new WP_Ajax_Response();
+		$ajax_response->send();
+
+		// Check the XML tag
+		$contents = ob_get_clean();
+		$this->assertRegExp( '/<\?xml\s+version=\'1.0\'\s+encoding=\'' . preg_quote( get_option( 'blog_charset' ) ) . '\'\s+standalone=\'yes\'\?>/', $contents );
+	}
+}