Refactor contracts tests to not use injected web3 instance

packages/dev-utils/src/web3_factory.ts

@@ -0,0 +1,42 @@
+// HACK: web3 injects XMLHttpRequest into the global scope and ProviderEngine checks XMLHttpRequest
+// to know whether it is running in a browser or node environment. We need it to be undefined since
+// we are not running in a browser env.
+// Filed issue: https://github.com/ethereum/web3.js/issues/844
+(global as any).XMLHttpRequest = undefined;
+import ProviderEngine = require('web3-provider-engine');
+import RpcSubprovider = require('web3-provider-engine/subproviders/rpc');
+
+import { EmptyWalletSubprovider } from './subproviders/empty_wallet_subprovider';
+import { FakeGasEstimateSubprovider } from './subproviders/fake_gas_estimate_subprovider';
+
+import { constants } from './constants';
+
+// HACK: web3 leaks XMLHttpRequest into the global scope and causes requests to hang
+// because they are using the wrong XHR package.
+// importing web3 after subproviders fixes this issue
+// Filed issue: https://github.com/ethereum/web3.js/issues/844
+// tslint:disable-next-line:ordered-imports
+import * as Web3 from 'web3';
+
+export const web3Factory = {
+    create(hasAddresses: boolean = true): Web3 {
+        const provider = this.getRpcProvider(hasAddresses);
+        const web3 = new Web3();
+        web3.setProvider(provider);
+        return web3;
+    },
+    getRpcProvider(hasAddresses: boolean = true): Web3.Provider {
+        const provider = new ProviderEngine();
+        if (!hasAddresses) {
+            provider.addProvider(new EmptyWalletSubprovider());
+        }
+        provider.addProvider(new FakeGasEstimateSubprovider(constants.GAS_ESTIMATE));
+        provider.addProvider(
+            new RpcSubprovider({
+                rpcUrl: constants.RPC_URL,
+            }),
+        );
+        provider.start();
+        return provider;
+    },
+};