1 files changed, 59 insertions, 0 deletions
diff --git a/dom/console/tests/xpcshell/test_worker.js b/dom/console/tests/xpcshell/test_worker.js
new file mode 100644
index 0000000000..7792dfc2da
--- /dev/null
+++ b/dom/console/tests/xpcshell/test_worker.js
@@ -0,0 +1,59 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests for console.createInstance usage in workers.
+ *
+ * Also tests that the use of `maxLogLevelPref` logs an error, and log levels
+ * fallback to the `maxLogLevel` option.
+ */
+
+"use strict";
+
+let { TestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TestUtils.sys.mjs"
+);
+
+add_task(async function () {
+  let endConsoleListening = TestUtils.listenForConsoleMessages();
+  let workerCompleteDeferred = Promise.withResolvers();
+
+  const worker = new ChromeWorker("resource://test/worker.mjs");
+  worker.onmessage = workerCompleteDeferred.resolve;
+  worker.postMessage({});
+
+  await workerCompleteDeferred.promise;
+
+  let messages = await endConsoleListening();
+
+  // Should log that we can't use `maxLogLevelPref`, and the warning message.
+  // The info message should not be logged, as that's lower than the specified
+  // `maxLogLevel` in the worker.
+  Assert.equal(messages.length, 2, "Should have received two messages");
+
+  // First message should be the error that `maxLogLevelPref` cannot be used.
+  Assert.equal(messages[0].level, "error", "Should be an error message");
+  Assert.equal(
+    messages[0].prefix,
+    "testPrefix",
+    "Should have the correct prefix"
+  );
+  Assert.equal(
+    messages[0].arguments[0],
+    "Console.maxLogLevelPref is not supported within workers!",
+    "Should have the correct message text"
+  );
+
+  // Second message should be the warning.
+  Assert.equal(messages[1].level, "warn", "Should be a warning message");
+  Assert.equal(
+    messages[1].prefix,
+    "testPrefix",
+    "Should have the correct prefix"
+  );
+  Assert.equal(
+    messages[1].arguments[0],
+    "Test Warn",
+    "Should have the correct message text"
+  );
+});