TestCaseTest::testStreamFilter() fails

[kenjis]

$ vendor/bin/phpunit tests/system/Test/
PHPUnit 9.5.21 #StandWithUkraine

Runtime:       PHP 8.0.20
Configuration: /Users/kenji/work/codeigniter/CodeIgniter4/phpunit.xml

...............................................................  63 / 206 ( 30%)
............................................................... 126 / 206 ( 61%)
.........................F..................................... 189 / 206 ( 91%)
.................                                               206 / 206 (100%)

Time: 00:04.397, Memory: 26.00 MB

There was 1 failure:

1) CodeIgniter\Test\TestCaseTest::testStreamFilter
Failed asserting that two strings are identical.
--- Expected
+++ Actual
@@ @@
-'first.
+'
+first.
 '

.../CodeIgniter4/tests/system/Test/TestCaseTest.php:60

FAILURES!
Tests: 206, Assertions: 306, Failures: 1.