1 files changed, 50 insertions, 1 deletions
diff --git a/cli/tests/unit/websocket_test.ts b/cli/tests/unit/websocket_test.ts
index 948e2add2..997d8f0df 100644
--- a/cli/tests/unit/websocket_test.ts
+++ b/cli/tests/unit/websocket_test.ts
@@ -1,5 +1,11 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
-import { assertEquals, assertThrows, deferred, fail } from "./test_util.ts";
+import {
+  assert,
+  assertEquals,
+  assertThrows,
+  deferred,
+  fail,
+} from "./test_util.ts";
 
 Deno.test({ permissions: "none" }, function websocketPermissionless() {
   assertThrows(
@@ -82,3 +88,46 @@ Deno.test(
     ws.close();
   },
 );
+
+// https://github.com/denoland/deno/issues/18775
+Deno.test({
+  sanitizeOps: false,
+  sanitizeResources: false,
+}, async function websocketDoubleClose() {
+  const promise = deferred();
+
+  const ac = new AbortController();
+  const listeningPromise = deferred();
+
+  const server = Deno.serve({
+    handler: (req) => {
+      const { response, socket } = Deno.upgradeWebSocket(req);
+      let called = false;
+      socket.onopen = () => socket.send("Hello");
+      socket.onmessage = () => {
+        assert(!called);
+        called = true;
+        socket.send("bye");
+        socket.close();
+      };
+      socket.onclose = () => ac.abort();
+      socket.onerror = () => fail();
+      return response;
+    },
+    signal: ac.signal,
+    onListen: () => listeningPromise.resolve(),
+    hostname: "localhost",
+    port: 4247,
+  });
+
+  await listeningPromise;
+
+  const ws = new WebSocket("ws://localhost:4247/");
+  assertEquals(ws.url, "ws://localhost:4247/");
+  ws.onerror = () => fail();
+  ws.onmessage = () => ws.send("bye");
+  ws.onclose = () => {
+    promise.resolve();
+  };
+  await Promise.all([promise, server]);
+});