diff --git a/src/Framework/TestCase.php b/src/Framework/TestCase.php
index 121a19795d9..08b8ab523c8 100644
--- a/src/Framework/TestCase.php
+++ b/src/Framework/TestCase.php
@@ -33,6 +33,7 @@
 use function is_int;
 use function is_object;
 use function is_string;
+use function is_writable;
 use function libxml_clear_errors;
 use function method_exists;
 use function ob_end_clean;
@@ -1298,34 +1299,46 @@ private function runTest(): mixed
         $testArguments = array_merge($this->data, array_values($this->dependencyInput));
 
         $capture = tmpfile();
-        assert($capture !== false);
 
         if (ini_get('display_errors') === '0') {
             ShutdownHandler::setMessage('Fatal error: Premature end of PHP process. Use display_errors=On to see the error message.');
         }
-        $errorLogPrevious = ini_set('error_log', stream_get_meta_data($capture)['uri']);
+
+        if ($capture !== false) {
+            $capturePath = stream_get_meta_data($capture)['uri'];
+
+            if (@is_writable($capturePath)) {
+                $errorLogPrevious = ini_set('error_log', $capturePath);
+            } else {
+                $capture = false;
+            }
+        }
 
         try {
             /** @phpstan-ignore method.dynamicName */
             $testResult = $this->{$this->methodName}(...$testArguments);
 
-            $errorLogOutput = stream_get_contents($capture);
+            if ($capture !== false) {
+                $errorLogOutput = stream_get_contents($capture);
 
-            if ($this->expectErrorLog) {
-                $this->assertNotEmpty($errorLogOutput, 'Test did not call error_log().');
-            } else {
-                if ($errorLogOutput !== false) {
-                    // strip date from logged error, see https://github.com/php/php-src/blob/c696087e323263e941774ebbf902ac249774ec9f/main/main.c#L905
-                    print preg_replace('/\[.+\] /', '', $errorLogOutput);
+                if ($this->expectErrorLog) {
+                    $this->assertNotEmpty($errorLogOutput, 'Test did not call error_log().');
+                } else {
+                    if ($errorLogOutput !== false) {
+                        print $this->stripDateFromErrorLog($errorLogOutput);
+                    }
                 }
+            } elseif ($this->expectErrorLog) {
+                $this->markTestIncomplete('Could not create writable error_log file.');
             }
         } catch (Throwable $exception) {
-            if (!$this->expectErrorLog) {
-                $errorLogOutput = stream_get_contents($capture);
+            if ($capture !== false) {
+                if (!$this->expectErrorLog) {
+                    $errorLogOutput = stream_get_contents($capture);
 
-                if ($errorLogOutput !== false) {
-                    // strip date from logged error, see https://github.com/php/php-src/blob/c696087e323263e941774ebbf902ac249774ec9f/main/main.c#L905
-                    print preg_replace('/\[.+\] /', '', $errorLogOutput);
+                    if ($errorLogOutput !== false) {
+                        print $this->stripDateFromErrorLog($errorLogOutput);
+                    }
                 }
             }
 
@@ -1337,10 +1350,13 @@ private function runTest(): mixed
 
             return null;
         } finally {
-            ShutdownHandler::resetMessage();
-            fclose($capture);
+            if ($capture !== false) {
+                ShutdownHandler::resetMessage();
+                fclose($capture);
 
-            ini_set('error_log', $errorLogPrevious);
+                /** @phpstan-ignore variable.undefined (https://github.com/phpstan/phpstan/issues/12992) */
+                ini_set('error_log', $errorLogPrevious);
+            }
         }
 
         $this->expectedExceptionWasNotRaised();
@@ -1348,6 +1364,12 @@ private function runTest(): mixed
         return $testResult;
     }
 
+    private function stripDateFromErrorLog(string $log): string
+    {
+        // https://github.com/php/php-src/blob/c696087e323263e941774ebbf902ac249774ec9f/main/main.c#L905
+        return preg_replace('/\[\d+-\w+-\d+ \d+:\d+:\d+ [^\r\n[\]]+?\] /', '', $log);
+    }
+
     /**
      * @throws ExpectationFailedException
      */
diff --git a/tests/end-to-end/generic/expect-error-log-fail-with-open_basedir.phpt b/tests/end-to-end/generic/expect-error-log-fail-with-open_basedir.phpt
new file mode 100644
index 00000000000..a511ade932f
--- /dev/null
+++ b/tests/end-to-end/generic/expect-error-log-fail-with-open_basedir.phpt
@@ -0,0 +1,42 @@
+--TEST--
+https://github.com/sebastianbergmann/phpunit/issues/6197
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = '--testdox';
+$_SERVER['argv'][] = __DIR__ . '/_files/ExpectErrorLogFailTest.php';
+
+/*
+ * Expected result should match the result of expect-error-log-fail-with-open_basedir.phpt test,
+ * but at least one of these feature requests needs to be implemented in php-src:
+ * - https://github.com/php/php-src/issues/17817
+ * - https://github.com/php/php-src/issues/18530
+ *
+ * Until then, mark the test result as incomplete when TestCase::expectErrorLog() was called and an error_log file
+ * could not be created (because of open_basedir php.ini in effect, readonly filesystem...).
+ */
+
+ini_set('open_basedir', (ini_get('open_basedir') ? ini_get('open_basedir') . PATH_SEPARATOR : '') . dirname(__DIR__, 3));
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+(new PHPUnit\TextUI\Application)->run($_SERVER['argv']);
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Runtime: %s
+
+I                                                                   1 / 1 (100%)
+
+Time: %s, Memory: %s
+
+Expect Error Log Fail (PHPUnit\TestFixture\ExpectNoErrorLog\ExpectErrorLogFail)
+ ∅ One
+   │
+   │ Could not create writable error_log file.
+
+   │
+
+OK, but there were issues!
+Tests: 1, Assertions: 1, Incomplete: 1.
diff --git a/tests/end-to-end/generic/expect-error-log-with-open_basedir.phpt b/tests/end-to-end/generic/expect-error-log-with-open_basedir.phpt
new file mode 100644
index 00000000000..d0218ba6558
--- /dev/null
+++ b/tests/end-to-end/generic/expect-error-log-with-open_basedir.phpt
@@ -0,0 +1,33 @@
+--TEST--
+https://github.com/sebastianbergmann/phpunit/issues/6197
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = '--testdox';
+$_SERVER['argv'][] = __DIR__ . '/_files/ExpectErrorLogTest.php';
+
+ini_set('open_basedir', (ini_get('open_basedir') ? ini_get('open_basedir') . PATH_SEPARATOR : '') . dirname(__DIR__, 3));
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+(new PHPUnit\TextUI\Application)->run($_SERVER['argv']);
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Runtime: %s
+
+logged a side effect
+I                                                                   1 / 1 (100%)
+
+Time: %s, Memory: %s
+
+Expect Error Log (PHPUnit\TestFixture\ExpectErrorLog\ExpectErrorLog)
+ ∅ One
+   │
+   │ Could not create writable error_log file.
+
+   │
+
+OK, but there were issues!
+Tests: 1, Assertions: 1, Incomplete: 1.