Test error_log() in tests

tests/end-to-end/regression/2155.phpt

@@ -0,0 +1,25 @@
+--TEST--
+https://github.com/sebastianbergmann/phpunit/issues/2155
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = '--testdox';
+$_SERVER['argv'][] = __DIR__ . '/2155/Issue2155Test.php';
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+(new PHPUnit\TextUI\Application)->run($_SERVER['argv']);
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Runtime: %s
+
+.                                                                   1 / 1 (100%)
+
+Time: %s, Memory: %s
+
+Issue2155 (PHPUnit\TestFixture\Issue2155\Issue2155)
+ ✔ One
+
+OK (1 test, 2 assertions)

tests/end-to-end/regression/2155/Issue2155Test.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\TestFixture\Issue2155;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\TestDox;
+use PHPUnit\Framework\TestCase;
+
+class Foo {
+    public function doFoo() {
+        error_log('logged a side effect');
+
+        return '';
+    }
+}
+
+final class Issue2155Test extends TestCase
+{
+    public function testOne(): void
+    {
+        $foo = new Foo();
+
+        self::assertSame('', $foo->doFoo());
+        self::expectErrorOutputRegex('/logged a side effect/');
+    }
+}