public function test_sanitize() {
    do_action( 'customize_register', $this->wp_customize );
    $setting = new WP_Customize_Nav_Menu_Setting( $this->wp_customize, 'nav_menu[123]' );

    $this->assertNull( $setting->sanitize( 'not an array' ) );
    $this->assertNull( $setting->sanitize( 123 ) );

    $value     = array(
      'name'        => ' Hello \\o/ <b>world</b> ',
      'description' => "New\nline \\o/",
      'parent'      => -12,
      'auto_add'    => true,
      'extra'       => 'ignored',
    );
    $sanitized = $setting->sanitize( $value );
    $this->assertSame( 'Hello \\o/ &lt;b&gt;world&lt;/b&gt;', $sanitized['name'] );
    $this->assertSame( 'New line \\o/', $sanitized['description'] );
    $this->assertSame( 0, $sanitized['parent'] );
    $this->assertTrue( $sanitized['auto_add'] );
    $this->assertSameSets( array( 'name', 'description', 'parent', 'auto_add' ), array_keys( $sanitized ) );

    $value['name'] = '    '; // Blank spaces.
    $sanitized     = $setting->sanitize( $value );
    $this->assertSame( '(unnamed)', $sanitized['name'] );
  }