diff --git a/tests/FirstTest.php b/tests/FirstTest.php
index b5be03b..0b33391 100644
--- a/tests/FirstTest.php
+++ b/tests/FirstTest.php
@@ -115,7 +115,9 @@ public function testCancelPendingStreamWillReject()
 
     public function testShouldResolveWithoutCreatingGarbageCyclesAfterDataThenClose()
     {
-        \gc_collect_cycles();
+        while (gc_collect_cycles()) {
+            // collect all garbage cycles
+        }
 
         $stream = new ThroughStream();
 
@@ -130,7 +132,10 @@ public function testShouldResolveWithoutCreatingGarbageCyclesAfterDataThenClose(
 
     public function testCancelPendingStreamWillRejectWithoutCreatingGarbageCycles()
     {
-        \gc_collect_cycles();
+        while (gc_collect_cycles()) {
+            // collect all garbage cycles
+        }
+
         $stream = new ThroughStream();
 
         $promise = Stream\first($stream);