Merge branch 'development' into feature/portal-ledger-support

* development: (437 commits)
  Publish
  Update yarn.lock
  Update the CHANGELOG
  Fix the bug making it impossible to specify the custom ZRX address
  Fix fill/cancel order by looking for NoError instead of empty blockchainErr given the BlockchainErrs type refactor
  Add a comment about a yarn bug
  Add our mainnet and kovan nodes as backups for Portal requests
  Fix bug hiding the user info from topBar
  Add dev-utils package to top level README
  Prettier newline
  Prettier
  Allow Token symbols to be alphanumeric
  Update CHANGELOG, rebase on development
  Should not -> cannot
  Reject negative amounts in isValidBaseUnitAmount
  Re-add changelog for 0x.js
  Fix prettier
  Update yarn.lock
  Move tests to a separate folder
  Change file layout
  ...

# Conflicts:
#	packages/website/README.md

1 files changed, 23 insertions, 0 deletions

diff --git a/packages/dev-utils/src/blockchain_lifecycle.ts b/packages/dev-utils/src/blockchain_lifecycle.ts
new file mode 100644
index 000000000..18f5d5c61
--- /dev/null
+++ b/packages/dev-utils/src/blockchain_lifecycle.ts
@@ -0,0 +1,23 @@
+import { RPC } from './rpc';
+
+export class BlockchainLifecycle {
+    private _rpc: RPC;
+    private _snapshotIdsStack: number[];
+    constructor(url: string) {
+        this._rpc = new RPC(url);
+        this._snapshotIdsStack = [];
+    }
+    // TODO: In order to run these tests on an actual node, we should check if we are running against
+    // TestRPC, if so, use snapshots, otherwise re-deploy contracts before every test
+    public async startAsync(): Promise<void> {
+        const snapshotId = await this._rpc.takeSnapshotAsync();
+        this._snapshotIdsStack.push(snapshotId);
+    }
+    public async revertAsync(): Promise<void> {
+        const snapshotId = this._snapshotIdsStack.pop() as number;
+        const didRevert = await this._rpc.revertSnapshotAsync(snapshotId);
+        if (!didRevert) {
+            throw new Error(`Snapshot with id #${snapshotId} failed to revert`);
+        }
+    }
+}