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

packages/subproviders/test/unit/ledger_subprovider_test.ts

@@ -2,6 +2,7 @@ import { JSONRPCResponsePayload } from '@0xproject/types';
 import * as chai from 'chai';
 import * as ethUtils from 'ethereumjs-util';
 import * as _ from 'lodash';
+import 'make-promises-safe';
 import Web3 = require('web3');
 import Web3ProviderEngine = require('web3-provider-engine');
 

packages/subproviders/test/unit/mnemonic_wallet_subprovider_test.ts

@@ -2,6 +2,7 @@ import { JSONRPCResponsePayload } from '@0xproject/types';
 import * as chai from 'chai';
 import * as ethUtils from 'ethereumjs-util';
 import * as _ from 'lodash';
+import 'make-promises-safe';
 import Web3ProviderEngine = require('web3-provider-engine');
 
 import { GanacheSubprovider, MnemonicWalletSubprovider } from '../../src/';

packages/subproviders/test/unit/nonce_tracker_subprovider_test.ts

@@ -1,6 +1,7 @@
 import * as chai from 'chai';
 import * as fs from 'fs';
 import * as _ from 'lodash';
+import 'make-promises-safe';
 import * as path from 'path';
 import Web3ProviderEngine = require('web3-provider-engine');
 import FixtureSubprovider = require('web3-provider-engine/subproviders/fixture');

packages/subproviders/test/unit/private_key_wallet_subprovider_test.ts

@@ -2,6 +2,7 @@ import { JSONRPCResponsePayload } from '@0xproject/types';
 import * as chai from 'chai';
 import * as ethUtils from 'ethereumjs-util';
 import * as _ from 'lodash';
+import 'make-promises-safe';
 import Web3ProviderEngine = require('web3-provider-engine');
 
 import { GanacheSubprovider, PrivateKeyWalletSubprovider } from '../../src/';

packages/subproviders/test/unit/redundant_rpc_subprovider_test.ts

@@ -1,6 +1,7 @@
 import { DoneCallback, JSONRPCResponsePayload } from '@0xproject/types';
 import * as chai from 'chai';
 import * as _ from 'lodash';
+import 'make-promises-safe';
 import Web3 = require('web3');
 import Web3ProviderEngine = require('web3-provider-engine');
 import RpcSubprovider = require('web3-provider-engine/subproviders/rpc');