1 files changed, 36 insertions, 4 deletions
diff --git a/cli/tests/workers/test.ts b/cli/tests/workers/test.ts
index c3ccebfbb..41988d204 100644
--- a/cli/tests/workers/test.ts
+++ b/cli/tests/workers/test.ts
@@ -198,15 +198,12 @@ Deno.test({
     );
 
     racyWorker.onmessage = (e): void => {
-      assertEquals(e.data.buf.length, 999999);
-      racyWorker.onmessage = (_e): void => {
-        throw new Error("unreachable");
-      };
       setTimeout(() => {
         promise.resolve();
       }, 100);
     };
 
+    racyWorker.postMessage("START");
     await promise;
   },
 });
@@ -726,3 +723,38 @@ Deno.test({
     worker.terminate();
   },
 });
+
+Deno.test({
+  name: "structured cloning postMessage",
+  fn: async function (): Promise<void> {
+    const result = deferred();
+    const worker = new Worker(
+      new URL("worker_structured_cloning.ts", import.meta.url).href,
+      { type: "module" },
+    );
+
+    worker.onmessage = (e): void => {
+      // self field should reference itself (circular ref)
+      const value = e.data.self.self.self;
+
+      // fields a and b refer to the same array
+      assertEquals(value.a, ["a", true, 432]);
+      assertEquals(value.a, ["a", true, 432]);
+      value.b[0] = "b";
+      value.a[2] += 5;
+      assertEquals(value.a, ["b", true, 437]);
+      assertEquals(value.b, ["b", true, 437]);
+
+      const len = value.c.size;
+      value.c.add(1); // This value is already in the set.
+      value.c.add(2);
+      assertEquals(len + 1, value.c.size);
+
+      result.resolve();
+    };
+
+    worker.postMessage("START");
+    await result;
+    worker.terminate();
+  },
+});