tests - unit - fail on unhandled promise rejection

1 files changed, 45 insertions, 4 deletions

diff --git a/test/helper.js b/test/helper.js
index a01ea1e53..dd22d80b4 100644
--- a/test/helper.js
+++ b/test/helper.js
@@ -1,11 +1,52 @@
+// disallow promises from swallowing errors
+enableFailureOnUnhandledPromiseRejection()
+
+// logging util
 var log = require('loglevel')
 log.setDefaultLevel(5)
+global.log = log
 
+//
+// polyfills
+//
+
+// dom
 require('jsdom-global')()
+
+// localStorage
 window.localStorage = {}
 
-if (!('crypto' in window)) { window.crypto = {} }
-window.crypto.getRandomValues = require('polyfill-crypto.getrandomvalues')
+// crypto.getRandomValues
+if (!window.crypto) window.crypto = {}
+if (!window.crypto.getRandomValues) window.crypto.getRandomValues = require('polyfill-crypto.getrandomvalues')
 
-window.log = log
-global.log = log
+
+
+function enableFailureOnUnhandledPromiseRejection() {
+  // overwrite node's promise with the stricter Bluebird promise
+  global.Promise = require('bluebird')
+
+  // rethrow unhandledRejections
+  if (typeof process !== 'undefined') {
+    process.on('unhandledRejection', function (reason) {
+      throw reason;
+    });
+  } else if (typeof window !== 'undefined') {
+    // 2016-02-01: No browsers support this natively, however bluebird, when.js,
+    // and probably other libraries do.
+    if (typeof window.addEventListener === 'function') {
+      window.addEventListener('unhandledrejection', function (evt) {
+        throw evt.detail.reason;
+      });
+    } else {
+      var oldOHR = window.onunhandledrejection;
+      window.onunhandledrejection = function (evt) {
+        if (typeof oldOHR === 'function') oldOHR.apply(this, arguments);
+        throw evt.detail.reason;
+      };
+    }
+  } else if (typeof console !== 'undefined' &&
+      typeof (console.error || console.log) === 'function') {
+    (console.error || console.log)('Unhandled rejections will be ignored!');
+  }
+}
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