diff --git a/ext/zend_test/tests/observer_retval_01.phpt b/ext/zend_test/tests/observer_retval_01.phpt
index d58cac807d2..844d9037f34 100644
--- a/ext/zend_test/tests/observer_retval_01.phpt
+++ b/ext/zend_test/tests/observer_retval_01.phpt
@@ -6,6 +6,7 @@ Observer: Retvals are observable that are: IS_CONST
 zend_test.observer.enabled=1
 zend_test.observer.observe_all=1
 zend_test.observer.show_return_value=1
+opcache.optimization_level=0
 --FILE--
 <?php
 function foo() {
diff --git a/ext/zend_test/tests/observer_retval_by_ref_03.phpt b/ext/zend_test/tests/observer_retval_by_ref_03.phpt
index 50fe23add1f..f09174fc22e 100644
--- a/ext/zend_test/tests/observer_retval_by_ref_03.phpt
+++ b/ext/zend_test/tests/observer_retval_by_ref_03.phpt
@@ -6,6 +6,7 @@ Observer: Retvals by reference are observable that are: IS_VAR, ZEND_RETURNS_FUN
 zend_test.observer.enabled=1
 zend_test.observer.observe_all=1
 zend_test.observer.show_return_value=1
+opcache.optimization_level=0
 --FILE--
 <?php
 function getMessage() {
diff --git a/ext/zend_test/tests/observer_shutdown_01.phpt b/ext/zend_test/tests/observer_shutdown_01.phpt
index 16ea9cef0e2..04784cd1752 100644
--- a/ext/zend_test/tests/observer_shutdown_01.phpt
+++ b/ext/zend_test/tests/observer_shutdown_01.phpt
@@ -12,31 +12,31 @@ register_shutdown_function(function () {
     echo 'Shutdown: ' . foo() . PHP_EOL;
 });
 
-function bar() {
-    return 42;
+function bar($arg) {
+    return $arg;
 }
 
 function foo() {
-    bar();
-    return bar();
+    bar(41);
+    return bar(42);
 }
 
-echo 'Done: ' . bar() . PHP_EOL;
+echo 'Done: ' . bar(40) . PHP_EOL;
 ?>
 --EXPECTF--
 <!-- init '%s/observer_shutdown_%d.php' -->
 <file '%s/observer_shutdown_%d.php'>
   <!-- init bar() -->
   <bar>
-  </bar:42>
-Done: 42
+  </bar:40>
+Done: 40
 </file '%s/observer_shutdown_%d.php'>
 <!-- init {closure}() -->
 <{closure}>
   <!-- init foo() -->
   <foo>
     <bar>
-    </bar:42>
+    </bar:41>
     <bar>
     </bar:42>
   </foo:42>
diff --git a/ext/zend_test/tests/observer_shutdown_02.phpt b/ext/zend_test/tests/observer_shutdown_02.phpt
index ad6c9065856..b666a92e150 100644
--- a/ext/zend_test/tests/observer_shutdown_02.phpt
+++ b/ext/zend_test/tests/observer_shutdown_02.phpt
@@ -16,33 +16,33 @@ class MyClass
     }
 }
 
-function bar() {
-    return 42;
+function bar($arg) {
+    return $arg;
 }
 
 function foo() {
-    bar();
-    return bar();
+    bar(41);
+    return bar(42);
 }
 
 $mc = new MyClass();
 
-echo 'Done: ' . bar() . PHP_EOL;
+echo 'Done: ' . bar(40) . PHP_EOL;
 ?>
 --EXPECTF--
 <!-- init '%s/observer_shutdown_%d.php' -->
 <file '%s/observer_shutdown_%d.php'>
   <!-- init bar() -->
   <bar>
-  </bar:42>
-Done: 42
+  </bar:40>
+Done: 40
 </file '%s/observer_shutdown_%d.php'>
 <!-- init MyClass::__destruct() -->
 <MyClass::__destruct>
   <!-- init foo() -->
   <foo>
     <bar>
-    </bar:42>
+    </bar:41>
     <bar>
     </bar:42>
   </foo:42>