Make coverage a module instead of a function

packages/dev-utils/src/coverage.ts

@@ -3,12 +3,17 @@ import * as _ from 'lodash';
 
 let coverageSubprovider: CoverageSubprovider;
 
-export function getCoverageSubproviderSingleton(): CoverageSubprovider {
-    if (_.isUndefined(coverageSubprovider)) {
+export const coverage = {
+    getCoverageSubproviderSingleton(): CoverageSubprovider {
+        if (_.isUndefined(coverageSubprovider)) {
+            coverageSubprovider = coverage._getCoverageSubprovider();
+        }
+        return coverageSubprovider;
+    },
+    _getCoverageSubprovider(): CoverageSubprovider {
         const artifactsPath = './src/artifacts';
         const contractsPath = './src/contracts';
         const networkId = 50;
-        coverageSubprovider = new CoverageSubprovider(artifactsPath, contractsPath, networkId);
-    }
-    return coverageSubprovider;
-}
+        return new CoverageSubprovider(artifactsPath, contractsPath, networkId);
+    },
+};

packages/dev-utils/src/index.ts

@@ -1,4 +1,4 @@
 export { BlockchainLifecycle } from './blockchain_lifecycle';
 export { web3Factory } from './web3_factory';
 export { constants as devConstants } from './constants';
-export { getCoverageSubproviderSingleton } from './coverage';
+export { coverage } from './coverage';

packages/dev-utils/src/web3_factory.ts

@@ -12,7 +12,7 @@ import * as _ from 'lodash';
 import * as process from 'process';
 
 import { constants } from './constants';
-import { getCoverageSubproviderSingleton } from './coverage';
+import { coverage } from './coverage';
 
 // HACK: web3 leaks XMLHttpRequest into the global scope and causes requests to hang
 // because they are using the wrong XHR package.
@@ -36,7 +36,7 @@ export const web3Factory = {
     getRpcProvider(config: Web3Config = {}): Web3.Provider {
         const provider = new ProviderEngine();
         if (process.env.SOLIDITY_COVERAGE) {
-            provider.addProvider(getCoverageSubproviderSingleton());
+            provider.addProvider(coverage.getCoverageSubproviderSingleton());
         }
         const hasAddresses = _.isUndefined(config.hasAddresses) || config.hasAddresses;
         if (!hasAddresses) {