Use make-promises-safe to catch unhandled rejections in tests

packages/assert/package.json

@@ -2,7 +2,7 @@
     "name": "@0xproject/assert",
     "version": "0.2.9",
     "engines": {
-        "node" : ">=6.12"
+        "node": ">=6.12"
     },
     "description": "Provides a standard way of performing type and schema validation across 0x projects",
     "main": "lib/src/index.js",
@@ -38,6 +38,7 @@
         "chai": "^4.0.1",
         "copyfiles": "^1.2.0",
         "dirty-chai": "^2.0.1",
+        "make-promises-safe": "^1.1.0",
         "mocha": "^4.0.1",
         "npm-run-all": "^4.1.2",
         "nyc": "^11.0.1",

packages/assert/test/assert_test.ts

@@ -2,6 +2,7 @@ import { schemas } from '@0xproject/json-schemas';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import * as dirtyChai from 'dirty-chai';
+import 'make-promises-safe';
 import 'mocha';
 
 import { assert } from '../src/index';