3 files changed, 32 insertions, 0 deletions
diff --git a/cli/tests/testdata/worker_close_in_wasm_reactions.js b/cli/tests/testdata/worker_close_in_wasm_reactions.js
new file mode 100644
index 000000000..2f5ea32d5
--- /dev/null
+++ b/cli/tests/testdata/worker_close_in_wasm_reactions.js
@@ -0,0 +1,10 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+// https://github.com/denoland/deno/issues/12263
+// Test for a panic that happens when a worker is closed in the reactions of a
+// WASM async operation.
+
+new Worker(
+  new URL("./workers/close_in_wasm_reactions.js", import.meta.url),
+  { type: "module" },
+);
diff --git a/cli/tests/testdata/worker_close_in_wasm_reactions.js.out b/cli/tests/testdata/worker_close_in_wasm_reactions.js.out
new file mode 100644
index 000000000..eef017a96
--- /dev/null
+++ b/cli/tests/testdata/worker_close_in_wasm_reactions.js.out
@@ -0,0 +1 @@
+Error: CompileError: WebAssembly.compile(): expected string length @+10
diff --git a/cli/tests/testdata/workers/close_in_wasm_reactions.js b/cli/tests/testdata/workers/close_in_wasm_reactions.js
new file mode 100644
index 000000000..abe573108
--- /dev/null
+++ b/cli/tests/testdata/workers/close_in_wasm_reactions.js
@@ -0,0 +1,21 @@
+// https://github.com/denoland/deno/issues/12263
+// Test for a panic that happens when a worker is closed in the reactions of a
+// WASM async operation.
+
+// The minimum valid wasm module, plus two additional zero bytes.
+const buffer = new Uint8Array([
+  0x00,
+  0x61,
+  0x73,
+  0x6D,
+  0x01,
+  0x00,
+  0x00,
+  0x00,
+  0x00,
+  0x00,
+]);
+WebAssembly.compile(buffer).catch((err) => {
+  console.log("Error:", err);
+  self.close();
+});