Refactor integrations directory structure; move core.ts, balance stores, and FillOrderWrapper to integrations

contracts/integrations/test/framework/simulation.ts

@@ -0,0 +1,38 @@
+import { GlobalStakeByStatus, StakeStatus, StakingPoolById, StoredBalance } from '@0x/contracts-staking';
+import * as _ from 'lodash';
+
+import { AssertionResult } from './assertions/function_assertion';
+import { BlockchainBalanceStore } from './balances/blockchain_balance_store';
+import { DeploymentManager } from './deployment_manager';
+
+// tslint:disable:max-classes-per-file
+
+export class SimulationEnvironment {
+    public globalStake: GlobalStakeByStatus = {
+        [StakeStatus.Undelegated]: new StoredBalance(),
+        [StakeStatus.Delegated]: new StoredBalance(),
+    };
+    public stakingPools: StakingPoolById = {};
+
+    public constructor(public readonly deployment: DeploymentManager, public balanceStore: BlockchainBalanceStore) {}
+}
+
+export abstract class Simulation {
+    public readonly generator = this._assertionGenerator();
+
+    constructor(public environment: SimulationEnvironment) {}
+
+    public async fuzzAsync(steps?: number): Promise<void> {
+        if (steps !== undefined) {
+            for (let i = 0; i < steps; i++) {
+                await this.generator.next();
+            }
+        } else {
+            while (true) {
+                await this.generator.next();
+            }
+        }
+    }
+
+    protected abstract _assertionGenerator(): AsyncIterableIterator<AssertionResult | void>;
+}