Properly and consistently parse ENV vars

packages/contracts/test/global_hooks.ts

@@ -1,7 +1,7 @@
-import { coverage } from '@0xproject/dev-utils';
+import { coverage, env, EnvVars } from '@0xproject/dev-utils';
 
 after('generate coverage report', async () => {
-    if (process.env.SOLIDITY_COVERAGE) {
+    if (env.parseBoolean(EnvVars.SolidityCoverage)) {
         const coverageSubprovider = coverage.getCoverageSubproviderSingleton();
         await coverageSubprovider.writeCoverageAsync();
     }

packages/dev-utils/src/env.ts

@@ -1,6 +1,11 @@
 import * as _ from 'lodash';
 import * as process from 'process';
 
+export enum EnvVars {
+    SolidityCoverage = 'SOLIDITY_COVERAGE',
+    VerboseGanache = 'VERBOSE_GANACHE',
+}
+
 export const env = {
     parseBoolean(key: string): boolean {
         let isTrue: boolean;

packages/dev-utils/src/index.ts

@@ -2,3 +2,4 @@ export { BlockchainLifecycle } from './blockchain_lifecycle';
 export { web3Factory } from './web3_factory';
 export { constants as devConstants } from './constants';
 export { coverage } from './coverage';
+export { env, EnvVars } from './env';

packages/dev-utils/src/web3_factory.ts

@@ -13,7 +13,7 @@ import * as process from 'process';
 
 import { constants } from './constants';
 import { coverage } from './coverage';
-import { env } from './env';
+import { env, EnvVars } from './env';
 
 // HACK: web3 leaks XMLHttpRequest into the global scope and causes requests to hang
 // because they are using the wrong XHR package.
@@ -27,11 +27,6 @@ export interface Web3Config {
     shouldUseInProcessGanache?: boolean; // default: false
 }
 
-enum EnvVars {
-    SolidityCoverage = 'SOLIDITY_COVERAGE',
-    VerboseGanache = 'VERBOSE_GANACHE',
-}
-
 export const web3Factory = {
     create(config: Web3Config = {}): Web3 {
         const provider = this.getRpcProvider(config);