fix: worker_message_before_close was flaky (#12019)

2 files changed, 19 insertions, 9 deletions

diff --git a/cli/tests/testdata/worker_message_before_close.js b/cli/tests/testdata/worker_message_before_close.js
index 6a9149af1..8ad35b3fc 100644
--- a/cli/tests/testdata/worker_message_before_close.js
+++ b/cli/tests/testdata/worker_message_before_close.js
@@ -1,16 +1,29 @@
+let messagesReceived = 0;
+
 for (let i = 0; i < 4; i++) {
   const worker = new Worker(
     new URL("./workers/message_before_close.js", import.meta.url).href,
     { type: "module", name: String(i) },
   );
 
-  worker.addEventListener("message", (message) => {
-    // Only print responses after all reception logs.
-    setTimeout(() => {
-      console.log("response from worker %d received", message.data);
-    }, 500);
+  worker.addEventListener("message", () => {
+    messagesReceived += 1;
+
+    if (messagesReceived == 4) {
+      console.log("received all 4 responses from the workers");
+    }
   });
+
   worker.postMessage(i);
 }
 
+globalThis.addEventListener("unload", () => {
+  if (messagesReceived !== 4) {
+    console.log(
+      "received only %d responses from the workers",
+      messagesReceived,
+    );
+  }
+});
+
 export {};
diff --git a/cli/tests/testdata/worker_message_before_close.js.out b/cli/tests/testdata/worker_message_before_close.js.out
index f1cc558a2..02a50ea95 100644
--- a/cli/tests/testdata/worker_message_before_close.js.out
+++ b/cli/tests/testdata/worker_message_before_close.js.out
@@ -2,7 +2,4 @@ message received in worker 0
 message received in worker 1
 message received in worker 2
 message received in worker 3
-response from worker 0 received
-response from worker 1 received
-response from worker 2 received
-response from worker 3 received
+received all 4 responses from the workers