1 files changed, 61 insertions, 0 deletions
diff --git a/browser/components/extensions/test/browser/browser_ext_lastError.js b/browser/components/extensions/test/browser/browser_ext_lastError.js
new file mode 100644
index 0000000000..f7015f131b
--- /dev/null
+++ b/browser/components/extensions/test/browser/browser_ext_lastError.js
@@ -0,0 +1,61 @@
+"use strict";
+
+async function sendMessage(options) {
+  function background(options) {
+    browser.runtime.sendMessage(result => {
+      browser.test.assertEq(undefined, result, "Argument value");
+      if (options.checkLastError) {
+        browser.test.assertEq(
+          "runtime.sendMessage's message argument is missing",
+          browser.runtime.lastError?.message,
+          "lastError value"
+        );
+      }
+      browser.test.sendMessage("done");
+    });
+  }
+
+  let extension = ExtensionTestUtils.loadExtension({
+    background: `(${background})(${JSON.stringify(options)})`,
+  });
+
+  await extension.startup();
+
+  await extension.awaitMessage("done");
+
+  await extension.unload();
+}
+
+add_task(async function testLastError() {
+  // Not necessary in browser-chrome tests, but monitorConsole gripes
+  // if we don't call it.
+  SimpleTest.waitForExplicitFinish();
+
+  // Check that we have no unexpected console messages when lastError is
+  // checked.
+  let waitForConsole = new Promise(resolve => {
+    SimpleTest.monitorConsole(resolve, [
+      { message: /message argument is missing/, forbid: true },
+    ]);
+  });
+
+  await sendMessage({ checkLastError: true });
+
+  SimpleTest.endMonitorConsole();
+  await waitForConsole;
+
+  // Check that we do have a console message when lastError is not checked.
+  waitForConsole = new Promise(resolve => {
+    SimpleTest.monitorConsole(resolve, [
+      {
+        message:
+          /Unchecked lastError value: Error: runtime.sendMessage's message argument is missing/,
+      },
+    ]);
+  });
+
+  await sendMessage({});
+
+  SimpleTest.endMonitorConsole();
+  await waitForConsole;
+});