diff --git a/src/Framework/TestCase.php b/src/Framework/TestCase.php
index 40ff2783ade..2edb160e919 100644
--- a/src/Framework/TestCase.php
+++ b/src/Framework/TestCase.php
@@ -686,11 +686,9 @@ public function run(TestResult $result = null): TestResult
             return $result;
         }
 
-        $runEntireClass =  $this->runClassInSeparateProcess && !$this->runTestInSeparateProcess;
+        if ($this->runInSeparateProcess()) {
+            $runEntireClass = $this->runClassInSeparateProcess && !$this->runTestInSeparateProcess;
 
-        if (($this->runTestInSeparateProcess === true || $this->runClassInSeparateProcess === true) &&
-            $this->inIsolation !== true &&
-            !$this instanceof PhptTestCase) {
             $class = new ReflectionClass($this);
 
             if ($runEntireClass) {
@@ -2114,4 +2112,10 @@ private function checkExceptionExpectations(Throwable $throwable): bool
 
         return $result;
     }
+
+    private function runInSeparateProcess(): bool
+    {
+        return ($this->runTestInSeparateProcess === true || $this->runClassInSeparateProcess === true) &&
+               $this->inIsolation !== true && !$this instanceof PhptTestCase;
+    }
 }