public function test_should_respect_number_format_of_locale() {
    $decimal_point = $GLOBALS['wp_locale']->number_format['decimal_point'];
    $thousands_sep = $GLOBALS['wp_locale']->number_format['thousands_sep'];

    $GLOBALS['wp_locale']->number_format['decimal_point'] = '@';
    $GLOBALS['wp_locale']->number_format['thousands_sep'] = '^';

    $actual_1 = number_format_i18n( 123456.789, 0 );
    $actual_2 = number_format_i18n( 123456.789, 4 );

    $GLOBALS['wp_locale']->number_format['decimal_point'] = $decimal_point;
    $GLOBALS['wp_locale']->number_format['thousands_sep'] = $thousands_sep;

    $this->assertSame( '123^457', $actual_1 );
    $this->assertSame( '123^456@7890', $actual_2 );
  }