Added more detailed assertions in Issue5592Test

Author: staabm

tests/end-to-end/regression/5592-process-isolation.phpt

@@ -52,4 +52,4 @@ Test code or tested code removed error handlers other than its own
 %sIssue5592Test.php:%i
 
 FAILURES!
-Tests: 6, Assertions: 6, Failures: 4, Risky: 1.
+Tests: 6, Assertions: 10, Failures: 4, Risky: 1.

tests/end-to-end/regression/5592/Issue5592Test.php

@@ -14,19 +14,25 @@
 use function set_error_handler;
 use function set_exception_handler;
 use PHPUnit\Framework\TestCase;
+use PHPUnit\Runner\ErrorHandler;
+use Throwable;
 
 class Issue5592Test extends TestCase
 {
     public function testAddedAndRemovedErrorHandler(): void
     {
-        set_error_handler(static fn () => false);
+        $previous = set_error_handler([$this, 'addedAndRemovedErrorHandler']);
         restore_error_handler();
+
+        $this->assertInstanceOf(ErrorHandler::class, $previous);
         $this->assertTrue(true);
     }
 
     public function testAddedErrorHandler(): void
     {
-        set_error_handler(static fn () => false);
+        $previous = set_error_handler([$this, 'addedErrorHandler']);
+
+        $this->assertInstanceOf(ErrorHandler::class, $previous);
         $this->assertTrue(false);
     }
 
@@ -38,14 +44,18 @@ public function testRemovedErrorHandler(): void
 
     public function testAddedAndRemovedExceptionHandler(): void
     {
-        set_exception_handler(static fn () => null);
+        $previous = set_exception_handler([$this, 'addedAndRemovedExceptionHandler']);
         restore_exception_handler();
+
+        $this->assertNull($previous);
         $this->assertTrue(true);
     }
 
     public function testAddedExceptionHandler(): void
     {
-        set_exception_handler(static fn () => null);
+        $previous = set_exception_handler([$this, 'addedExceptionHandler']);
+
+        $this->assertNull($previous);
         $this->assertTrue(false);
     }
 
@@ -54,4 +64,20 @@ public function testRemovedExceptionHandler(): void
         restore_exception_handler();
         $this->assertTrue(false);
     }
+
+    public function addedAndRemovedErrorHandler($errno, $errstr, $errfile, $errline): void
+    {
+    }
+
+    public function addedErrorHandler($errno, $errstr, $errfile, $errline): void
+    {
+    }
+
+    public function addedAndRemovedExceptionHandler(Throwable $exception): void
+    {
+    }
+
+    public function addedExceptionHandler(Throwable $exception): void
+    {
+    }
 }