1 files changed, 17 insertions, 0 deletions
diff --git a/spec/javascripts/test_bundle.js b/spec/javascripts/test_bundle.js
index f0d51bd0902..075b72f35b2 100644
--- a/spec/javascripts/test_bundle.js
+++ b/spec/javascripts/test_bundle.js
@@ -22,6 +22,19 @@ window.gl = window.gl || {};
 window.gl.TEST_HOST = 'http://test.host';
 window.gon = window.gon || {};
 
+let hasUnhandledPromiseRejections = false;
+
+window.addEventListener('unhandledrejection', (event) => {
+  hasUnhandledPromiseRejections = true;
+  console.error('Unhandled promise rejection:');
+  console.error(event.reason.stack || event.reason);
+});
+
+const checkUnhandledPromiseRejections = (done) => {
+  expect(hasUnhandledPromiseRejections).toBe(false);
+  done();
+};
+
 // HACK: Chrome 59 disconnects if there are too many synchronous tests in a row
 // because it appears to lock up the thread that communicates to Karma's socket
 // This async beforeEach gets called on every spec and releases the JS thread long
@@ -63,6 +76,10 @@ testsContext.keys().forEach(function (path) {
   }
 });
 
+it('has no unhandled Promise rejections', (done) => {
+  setTimeout(checkUnhandledPromiseRejections(done), 1000);
+});
+
 // if we're generating coverage reports, make sure to include all files so
 // that we can catch files with 0% coverage
 // see: https://github.com/deepsweet/istanbul-instrumenter-loader/issues/15