Attach a stack trace to the it() block promise error generated if present.

Author: alexjeffburke

lib/notifyPendingPromise.js

@@ -23,7 +23,14 @@ function registerAfterEachHook() {
             afterEach(function () {
                 var error;
                 var testPassed = true;
-                if (pendingPromisesForTheCurrentTest.some(function (promise) {return promise.isPending();})) {
+                var pendingPromise = null;
+                pendingPromisesForTheCurrentTest.some(function (promise) {
+                    if (promise.isPending()) {
+                        pendingPromise = promise;
+                        return true;
+                    }
+                });
+                if (pendingPromise) {
                     var displayName;
                     if (this.currentTest) {
                         // mocha
@@ -34,6 +41,9 @@ function registerAfterEachHook() {
                         displayName = currentSpec.fullName;
                     }
                     error = new Error(displayName + ': You have created a promise that was not returned from the it block');
+                    if (pendingPromise.trace && pendingPromise.trace.stack) {
+                        error.message += '\n\n' + pendingPromise.trace.stack;
+                    }
                 }
                 pendingPromisesForTheCurrentTest = [];
                 if (error && testPassed) {