diff --git a/src/utils/tests/ParallelTest.php b/src/utils/tests/ParallelTest.php
index 2fbf8976e..c48e46b6e 100644
--- a/src/utils/tests/ParallelTest.php
+++ b/src/utils/tests/ParallelTest.php
@@ -24,7 +24,6 @@ class ParallelTest extends TestCase
 {
     public function testParallel()
     {
-        $id = Coroutine::id();
         // Closure
         $parallel = new Parallel();
         for ($i = 0; $i < 3; ++$i) {
@@ -33,7 +32,8 @@ class ParallelTest extends TestCase
             });
         }
         $result = $parallel->wait();
-        $this->assertSame([$id + 1, $id + 2, $id + 3], $result);
+        $id = $result[0];
+        $this->assertSame([$id, $id + 1, $id + 2], $result);
 
         // Array
         $parallel = new Parallel();
@@ -41,7 +41,8 @@ class ParallelTest extends TestCase
             $parallel->add([$this, 'returnCoId']);
         }
         $result = $parallel->wait();
-        $this->assertSame([$id + 4, $id + 5, $id + 6], $result);
+        $id = $result[0];
+        $this->assertSame([$id, $id + 1, $id + 2], $result);
     }
 
     public function returnCoId()