WP_Customize_Manager::set_preview_url PHP Method

    public function set_preview_url($preview_url)
    {
        $preview_url = esc_url_raw($preview_url);
        $this->preview_url = wp_validate_redirect($preview_url, home_url('/'));
    }

	/**
	 * Test get_return_url()/set_return_url() methods.
	 *
	 * @see WP_Customize_Manager::get_return_url()
	 * @see WP_Customize_Manager::set_return_url()
	 */
	function test_return_url() {
		wp_set_current_user( self::factory()->user->create( array( 'role' => 'author' ) ) );
		$this->assertEquals( home_url( '/' ), $this->manager->get_return_url() );

		wp_set_current_user( self::factory()->user->create( array( 'role' => 'administrator' ) ) );
		$this->assertTrue( current_user_can( 'edit_theme_options' ) );
		$this->assertEquals( home_url( '/' ), $this->manager->get_return_url() );

		$preview_url = home_url( '/foo/' );
		$this->manager->set_preview_url( $preview_url );
		$this->assertEquals( $preview_url, $this->manager->get_return_url() );

		$_SERVER['HTTP_REFERER'] = wp_slash( admin_url( 'customize.php' ) );
		$this->assertEquals( $preview_url, $this->manager->get_return_url() );

		// See #35355.
		$_SERVER['HTTP_REFERER'] = wp_slash( admin_url( 'wp-login.php' ) );
		$this->assertEquals( $preview_url, $this->manager->get_return_url() );

		$url = home_url( '/referred/' );
		$_SERVER['HTTP_REFERER'] = wp_slash( $url );
		$this->assertEquals( $url, $this->manager->get_return_url() );

		$url = 'http://badreferer.example.com/';
		$_SERVER['HTTP_REFERER'] = wp_slash( $url );
		$this->assertNotEquals( $url, $this->manager->get_return_url() );
		$this->assertEquals( $preview_url, $this->manager->get_return_url() );

		$this->manager->set_return_url( admin_url( 'edit.php?trashed=1' ) );
		$this->assertEquals( admin_url( 'edit.php' ), $this->manager->get_return_url() );
	}