1 files changed, 48 insertions, 0 deletions
diff --git a/devtools/client/webconsole/test/browser/browser_jsterm_await_concurrent.js b/devtools/client/webconsole/test/browser/browser_jsterm_await_concurrent.js
new file mode 100644
index 0000000000..8cd3978d2d
--- /dev/null
+++ b/devtools/client/webconsole/test/browser/browser_jsterm_await_concurrent.js
@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that multiple concurrent top-level await expressions work as expected.
+
+"use strict";
+
+const TEST_URI =
+  "data:text/html;charset=utf-8,<!DOCTYPE html>Web Console test top-level await";
+
+add_task(async function () {
+  // Enable await mapping.
+  await pushPref("devtools.debugger.features.map-await-expression", true);
+  const hud = await openNewTabAndConsole(TEST_URI);
+
+  await clearOutput(hud);
+  const delays = [3000, 500, 9000, 6000];
+  const inputs = delays.map(
+    delay => `await new Promise(
+    r => setTimeout(() => r("await-concurrent-" + ${delay}), ${delay}))`
+  );
+
+  // Let's wait for the message that sould be displayed last.
+  const onMessage = waitForMessageByType(
+    hud,
+    "await-concurrent-9000",
+    ".result"
+  );
+  for (const input of inputs) {
+    execute(hud, input);
+  }
+  await onMessage;
+
+  const messages = hud.ui.outputNode.querySelectorAll(".message .message-body");
+  const messagesText = Array.from(messages).map(n => n.textContent);
+  const expectedMessages = [
+    ...inputs,
+    `"await-concurrent-500"`,
+    `"await-concurrent-3000"`,
+    `"await-concurrent-6000"`,
+    `"await-concurrent-9000"`,
+  ];
+  is(
+    JSON.stringify(messagesText, null, 2),
+    JSON.stringify(expectedMessages, null, 2),
+    "The output contains the the expected messages, in the expected order"
+  );
+});