Use make-promises-safe as a preloader instead of manually importing

packages/assert/package.json

@@ -12,7 +12,7 @@
         "build": "tsc && copyfiles -u 3 './lib/src/monorepo_scripts/**/*' ./scripts",
         "clean": "shx rm -rf lib test_temp scripts",
         "lint": "tslint --project .",
-        "run_mocha": "mocha --require source-map-support/register lib/test/**/*_test.js --exit",
+        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe lib/test/**/*_test.js --exit",
         "prepublishOnly": "run-p build",
         "test": "yarn run_mocha",
         "rebuild_and_test": "run-s clean build test",

packages/assert/test/assert_test.ts

@@ -2,7 +2,6 @@ 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';