Attempt at testing (failing due to uncaught exception)

karma.conf.js

@@ -143,7 +143,11 @@ module.exports = config => {
           pattern: 'test/browser-specific/fixtures/esm.fixture.mjs',
           type: 'module'
         },
-        {pattern: 'test/browser-specific/esm.spec.mjs', type: 'module'}
+        {pattern: 'test/browser-specific/esm.spec.mjs', type: 'module'},
+        {
+          pattern: 'test/browser-specific/uncaught-exception.spec.mjs',
+          type: 'module'
+        }
       ];
       break;
     default:

test/browser-specific/uncaught-exception.spec.mjs

@@ -0,0 +1,27 @@
+import '/base/mocha.js';
+
+var Mocha = window.Mocha;
+var Suite = Mocha.Suite;
+var Runner = Mocha.Runner;
+
+mocha.allowUncaught()
+
+it('should include the stack of uncaught exceptions', function(done) {
+  var suite = new Suite('Suite', 'root');
+  var runner = new Runner(suite);
+  runner.allowUncaught = true;
+  var err;
+  runner.fail = function(e) {
+    err = e;
+  };
+
+  setTimeout(function throwTestError() {
+    throw new Error('test error');
+  }, 1);
+
+  setTimeout(function() {
+    expect(err, 'to be an', Error);
+    expect(err.stack, 'to contain', 'at throwTestError')
+    done();
+  }, 2);
+});