Adding fix

Author: kubawerlos

src/Util/PHP/AbstractPhpProcess.php

@@ -11,6 +11,7 @@
 
 use __PHP_Incomplete_Class;
 use ErrorException;
+use PHPUnit\Framework\AssertionFailedError;
 use PHPUnit\Framework\Exception;
 use PHPUnit\Framework\SyntheticError;
 use PHPUnit\Framework\Test;
@@ -248,6 +249,14 @@ private function processChildResult(Test $test, TestResult $result, string $stdo
 
                 $childResult = \unserialize(\str_replace("#!/usr/bin/env php\n", '', $stdout));
                 \restore_error_handler();
+
+                if ($childResult === false) {
+                    $result->addFailure(
+                        $test,
+                        new AssertionFailedError('Test was run in child process and ended unexpectedly'),
+                        $time
+                    );
+                }
             } catch (ErrorException $e) {
                 \restore_error_handler();
                 $childResult = false;