4 files changed, 95 insertions, 0 deletions
diff --git a/test/utils/blockchain_clean.ts b/test/utils/blockchain_clean.ts
new file mode 100644
index 000000000..6468dbec7
--- /dev/null
+++ b/test/utils/blockchain_clean.ts
@@ -0,0 +1,19 @@
+import {RPC} from './rpc';
+
+export class BlockchainClean {
+    private rpc: RPC;
+    private snapshotId: number;
+    constructor() {
+        this.rpc = new RPC();
+    }
+    // TODO: Check if running on TestRPC or on actual node, if actual node, re-deploy contracts instead
+    public async setupAsync() {
+        this.snapshotId = await this.rpc.takeSnapshotAsync();
+    }
+    public async restoreAsync() {
+        const didRevert = await this.rpc.revertSnapshotAsync(this.snapshotId);
+        if (!didRevert) {
+            throw new Error(`Snapshot with id #${this.snapshotId} failed to revert`);
+        }
+    }
+};
diff --git a/test/utils/constants.ts b/test/utils/constants.ts
new file mode 100644
index 000000000..aa1967f88
--- /dev/null
+++ b/test/utils/constants.ts
@@ -0,0 +1,5 @@
+export const constants = {
+    NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
+    RPC_HOST: 'localhost',
+    RPC_PORT: 8545,
+};
diff --git a/test/utils/rpc.ts b/test/utils/rpc.ts
new file mode 100644
index 000000000..b689a938c
--- /dev/null
+++ b/test/utils/rpc.ts
@@ -0,0 +1,48 @@
+import * as ethUtil from 'ethereumjs-util';
+import * as request from 'request-promise-native';
+import {constants} from './constants';
+
+export class RPC {
+    private host: string;
+    private port: number;
+    private id: number;
+    constructor() {
+        this.host = constants.RPC_HOST;
+        this.port = constants.RPC_PORT;
+        this.id = 0;
+    }
+    public async takeSnapshotAsync(): Promise<number> {
+        const method = 'evm_snapshot';
+        const params: any[] = [];
+        const payload = this.toPayload(method, params);
+        const snapshotIdHex = await this.sendAsync(payload);
+        const snapshotId = ethUtil.bufferToInt(ethUtil.toBuffer(snapshotIdHex));
+        return snapshotId;
+    }
+    public async revertSnapshotAsync(snapshotId: number): Promise<boolean> {
+        const method = 'evm_revert';
+        const params = [snapshotId];
+        const payload = this.toPayload(method, params);
+        const didRevert = await this.sendAsync(payload);
+        return didRevert;
+    }
+    private toPayload(method: string, params: any[] = []) {
+        const payload = JSON.stringify({
+            id: this.id,
+            method,
+            params,
+        });
+        this.id += 1;
+        return payload;
+    }
+    private async sendAsync(payload: string) {
+        const opts = {
+            method: 'POST',
+            uri: `http://${this.host}:${this.port}`,
+            body: payload,
+        };
+        const bodyString = await request(opts);
+        const body = JSON.parse(bodyString);
+        return body.result;
+    }
+}
diff --git a/test/utils/web3_factory.ts b/test/utils/web3_factory.ts
new file mode 100644
index 000000000..493fbc2df
--- /dev/null
+++ b/test/utils/web3_factory.ts
@@ -0,0 +1,23 @@
+// HACK: web3 injects XMLHttpRequest into the global scope and ProviderEngine checks XMLHttpRequest
+// to know whether it is running in a browser or node environment. We need it to be undefined since
+// we are not running in a browser env.
+// Filed issue: https://github.com/ethereum/web3.js/issues/844
+(global as any).XMLHttpRequest = undefined;
+import ProviderEngine = require('web3-provider-engine');
+import RpcSubprovider = require('web3-provider-engine/subproviders/rpc');
+import * as Web3 from 'web3';
+import {constants} from './constants';
+
+export const web3Factory = {
+    create(): Web3 {
+        const provider = new ProviderEngine();
+        const rpcUrl = `http://${constants.RPC_HOST}:${constants.RPC_PORT}`;
+        provider.addProvider(new RpcSubprovider({
+            rpcUrl,
+        }));
+        provider.start();
+        const web3 = new Web3();
+        web3.setProvider(provider);
+        return web3;
+    },
+};