running a PHPUnit test today gave me this strange result:

There was 1 failure:

1) AppStudioInternFormatServiceTest::testNumberToPercent
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'50 %'
+'50 %'

The test is on this function:

public static function numberToPercent(float $value): string
{
    $percent_formatter = NumberFormatter::create('de_DE', NumberFormatter::PERCENT);
    return $percent_formatter->format($value);
}

..and runs this way:

$this->assertEquals('50 %', FormatService::numberToPercent(0.5));

Same result when using the CLI:

php > $percent_formatter = NumberFormatter::create('de_DE', NumberFormatter::PERCENT);
php > $value1 = $percent_formatter->format('0.5');
php > $value2 = '50 %';
php > echo $value1;
50 %
php > echo $value2;
50 %
php > echo ($value1 === $value2) ? 'equal' : 'not equal';
not equal

This is weird… Thanks for any hint!