1 files changed, 25 insertions, 0 deletions
diff --git a/tests/testdata/workers/racy_worker.js b/tests/testdata/workers/racy_worker.js
new file mode 100644
index 000000000..0f66c6278
--- /dev/null
+++ b/tests/testdata/workers/racy_worker.js
@@ -0,0 +1,25 @@
+// See issue for details
+// https://github.com/denoland/deno/issues/4080
+//
+// After first received message, this worker schedules
+// [assert(), close(), assert()] ops on the same turn of microtask queue
+// All tasks after close should not make it
+
+onmessage = async function () {
+  let stage = 0;
+  await new Promise((_) => {
+    setTimeout(() => {
+      if (stage !== 0) throw "Unexpected stage";
+      stage = 1;
+    }, 50);
+    setTimeout(() => {
+      if (stage !== 1) throw "Unexpected stage";
+      stage = 2;
+      postMessage("DONE");
+      close();
+    }, 50);
+    setTimeout(() => {
+      throw "This should not be run";
+    }, 50);
+  });
+};