v6.x backport for common.crashOnUnhandledRejection

test/README.md

@@ -174,6 +174,13 @@ A stream to push an array into a REPL
 
 Blocks for `time` amount of time.
 
+### crashOnUnhandledRejection()
+
+Installs a `process.on('unhandledRejection')` handler that crashes the process
+after a tick. This is useful for tests that use Promises and need to make sure
+no unexpected rejections occur, because currently they result in silent
+failures.
+
 ### ddCommand(filename, kilobytes)
 * return [<Object>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)
 

test/common.js

@@ -552,3 +552,9 @@ exports.expectWarning = function(name, expected) {
     expected.splice(expected.indexOf(warning.message), 1);
   }, expected.length));
 };
+
+// Crash the process on unhandled rejections.
+exports.crashOnUnhandledRejection = function() {
+  process.on('unhandledRejection',
+             (err) => process.nextTick(() => { throw err; }));
+};