fix: add stacktrace to failed expect function call

lib/test.js

@@ -303,7 +303,12 @@ function wrapAssertFn(assertFn) {
 
   return function(res) {
     let badStack;
-    const err = assertFn(res);
+    let err;
+    try {
+      err = assertFn(res);
+    } catch (e) {
+      err = e;
+    }
     if (err instanceof Error && err.stack) {
       badStack = err.stack.replace(err.message, '').split('\n').slice(1);
       err.stack = [err.toString()]

test/supertest.js

@@ -9,6 +9,7 @@ const bodyParser = require('body-parser');
 const cookieParser = require('cookie-parser');
 const nock = require('nock');
 const request = require('../index.js');
+const throwError = require('./throwError');
 
 process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
 
@@ -748,9 +749,7 @@ describe('request(app)', function () {
 
       it('reports errors', function (done) {
         get
-          .expect(function (res) {
-            throw new Error('failed');
-          })
+          .expect(throwError('failed'))
           .end(function (err) {
             err.message.should.equal('failed');
             shouldIncludeStackWithThisFile(err);
@@ -774,9 +773,7 @@ describe('request(app)', function () {
 
       it('ensures truthy errors returned from asserts are throw to end', function (done) {
         get
-          .expect(function (res) {
-            return new Error('some descriptive error');
-          })
+          .expect(throwError('some descriptive error'))
           .end(function (err) {
             err.message.should.equal('some descriptive error');
             shouldIncludeStackWithThisFile(err);

test/throwError.js

@@ -0,0 +1,10 @@
+'use strict';
+
+/**
+ * This method needs to reside in its own module in order to properly test stack trace handling.
+ */
+module.exports = function throwError(message) {
+  return function() {
+    throw new Error(message);
+  };
+};