diff --git a/contracts/integrations/test/framework/actors/hybrids.ts b/contracts/integrations/test/framework/actors/hybrids.ts
index 7265b0fb93..51a73a43b2 100644
--- a/contracts/integrations/test/framework/actors/hybrids.ts
+++ b/contracts/integrations/test/framework/actors/hybrids.ts
@@ -3,9 +3,11 @@ import { KeeperMixin } from './keeper';
 import { MakerMixin } from './maker';
 import { PoolOperatorMixin } from './pool_operator';
 import { StakerMixin } from './staker';
+import { TakerMixin } from './taker';
 
 export class OperatorMaker extends PoolOperatorMixin(MakerMixin(Actor)) {}
 export class StakerMaker extends StakerMixin(MakerMixin(Actor)) {}
 export class StakerOperator extends StakerMixin(PoolOperatorMixin(Actor)) {}
 export class OperatorStakerMaker extends PoolOperatorMixin(StakerMixin(MakerMixin(Actor))) {}
 export class StakerKeeper extends StakerMixin(KeeperMixin(Actor)) {}
+export class MakerTaker extends MakerMixin(TakerMixin(Actor)) {}
diff --git a/contracts/integrations/test/framework/actors/maker.ts b/contracts/integrations/test/framework/actors/maker.ts
index e701e29306..b0dbdf9077 100644
--- a/contracts/integrations/test/framework/actors/maker.ts
+++ b/contracts/integrations/test/framework/actors/maker.ts
@@ -1,6 +1,10 @@
 import { constants, OrderFactory } from '@0x/contracts-test-utils';
 import { Order, SignedOrder } from '@0x/types';
 import { TransactionReceiptWithDecodedLogs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { AssertionResult } from '../assertions/function_assertion';
+import { validJoinStakingPoolAssertion } from '../assertions/joinStakingPool';
 
 import { Actor, ActorConfig, Constructor } from './base';
 
@@ -45,6 +49,12 @@ export function MakerMixin<TBase extends Constructor>(Base: TBase): TBase & Cons
                 ...orderConfig,
             };
             this.orderFactory = new OrderFactory(this.actor.privateKey, defaultOrderParams);
+
+            // Register this mixin's assertion generators
+            this.actor.simulationActions = {
+                ...this.actor.simulationActions,
+                validJoinStakingPool: this._validJoinStakingPool(),
+            };
         }
 
         /**
@@ -73,6 +83,19 @@ export function MakerMixin<TBase extends Constructor>(Base: TBase): TBase & Cons
                 from: this.actor.address,
             });
         }
+
+        private async *_validJoinStakingPool(): AsyncIterableIterator<AssertionResult | void> {
+            const { stakingPools } = this.actor.simulationEnvironment!;
+            const assertion = validJoinStakingPoolAssertion(this.actor.deployment);
+            while (true) {
+                const poolId = _.sample(Object.keys(stakingPools));
+                if (poolId === undefined) {
+                    yield undefined;
+                } else {
+                    yield assertion.executeAsync([poolId], { from: this.actor.address });
+                }
+            }
+        }
     };
 }
 
diff --git a/contracts/integrations/test/framework/actors/pool_member.ts b/contracts/integrations/test/framework/actors/pool_member.ts
deleted file mode 100644
index 160eb7371e..0000000000
--- a/contracts/integrations/test/framework/actors/pool_member.ts
+++ /dev/null
@@ -1,98 +0,0 @@
-import { constants, getRandomInteger } from '@0x/contracts-test-utils';
-import { TransactionReceiptWithDecodedLogs } from 'ethereum-types';
-import * as _ from 'lodash';
-
-import { validFillOrderCompleteFillAssertion } from '../assertions/fillOrder';
-import { AssertionResult } from '../assertions/function_assertion';
-import { validJoinStakingPoolAssertion } from '../assertions/joinStakingPool';
-
-import { Actor, Constructor } from './base';
-
-interface PoolMemberInterface {
-    joinStakingPoolAsync: (poolId: string) => Promise<TransactionReceiptWithDecodedLogs>;
-}
-
-/**
- * This mixin encapsulates functionaltiy associated with pool operators within the 0x ecosystem.
- * This includes creating staking pools and decreasing the operator share of a pool.
- */
-export function PoolMemberMixin<TBase extends Constructor>(Base: TBase): TBase & Constructor<PoolMemberInterface> {
-    return class extends Base {
-        public readonly actor: Actor;
-
-        /**
-         * The mixin pattern requires that this constructor uses `...args: any[]`, but this class
-         * really expects a single `ActorConfig` parameter (assuming `Actor` is used as the
-         * base class).
-         */
-        constructor(...args: any[]) {
-            // tslint:disable-next-line:no-inferred-empty-object-type
-            super(...args);
-            this.actor = (this as any) as Actor;
-
-            // Register this mixin's assertion generators
-            this.actor.simulationActions = {
-                ...this.actor.simulationActions,
-                validJoinStakingPool: this._validJoinStakingPool(),
-                validFillOrderCompleteFill: this._validFillOrderCompleteFill(),
-            };
-        }
-
-        /**
-         * Joins a new staking pool.
-         */
-        public async joinStakingPoolAsync(poolId: string): Promise<TransactionReceiptWithDecodedLogs> {
-            const stakingContract = this.actor.deployment.staking.stakingWrapper;
-            return stakingContract
-                .joinStakingPoolAsMaker(poolId)
-                .awaitTransactionSuccessAsync({ from: this.actor.address });
-        }
-
-        private async *_validJoinStakingPool(): AsyncIterableIterator<AssertionResult | void> {
-            const { stakingPools } = this.actor.simulationEnvironment!;
-            const assertion = validJoinStakingPoolAssertion(this.actor.deployment);
-            while (true) {
-                const poolId = _.sample(Object.keys(stakingPools));
-                if (poolId === undefined) {
-                    yield undefined;
-                } else {
-                    yield assertion.executeAsync({ args: [poolId], txData: { from: this.actor.address } });
-                }
-            }
-        }
-
-        private async *_validFillOrderCompleteFill(): AsyncIterableIterator<AssertionResult | void> {
-            const { marketMakers } = this.actor.simulationEnvironment!;
-            const assertion = validFillOrderCompleteFillAssertion(this.actor.deployment);
-            while (true) {
-                const maker = _.sample(marketMakers);
-                if (maker === undefined) {
-                    yield undefined;
-                } else {
-                    // Configure the maker's token balances so that the order will definitely be fillable.
-                    await Promise.all([
-                        ...this.actor.deployment.tokens.erc20.map(async token => maker.configureERC20TokenAsync(token)),
-                        ...this.actor.deployment.tokens.erc20.map(async token =>
-                            this.actor.configureERC20TokenAsync(token),
-                        ),
-                        this.actor.configureERC20TokenAsync(
-                            this.actor.deployment.tokens.weth,
-                            this.actor.deployment.staking.stakingProxy.address,
-                        ),
-                    ]);
-
-                    const order = await maker.signOrderAsync({
-                        makerAssetAmount: getRandomInteger(constants.ZERO_AMOUNT, constants.INITIAL_ERC20_BALANCE),
-                        takerAssetAmount: getRandomInteger(constants.ZERO_AMOUNT, constants.INITIAL_ERC20_BALANCE),
-                    });
-                    yield assertion.executeAsync({
-                        args: [order, order.takerAssetAmount, order.signature],
-                        txData: { from: this.actor.address },
-                    });
-                }
-            }
-        }
-    };
-}
-
-export class PoolMember extends PoolMemberMixin(Actor) {}
diff --git a/contracts/integrations/test/framework/actors/pool_operator.ts b/contracts/integrations/test/framework/actors/pool_operator.ts
index b888ead533..176e26fd06 100644
--- a/contracts/integrations/test/framework/actors/pool_operator.ts
+++ b/contracts/integrations/test/framework/actors/pool_operator.ts
@@ -84,7 +84,7 @@ export function PoolOperatorMixin<TBase extends Constructor>(Base: TBase): TBase
             const assertion = validCreateStakingPoolAssertion(this.actor.deployment, stakingPools);
             while (true) {
                 const operatorShare = getRandomInteger(0, constants.PPM).toNumber();
-                yield assertion.executeAsync({ args: [operatorShare, false], txData: { from: this.actor.address } });
+                yield assertion.executeAsync([operatorShare, false], { from: this.actor.address });
             }
         }
 
@@ -97,10 +97,7 @@ export function PoolOperatorMixin<TBase extends Constructor>(Base: TBase): TBase
                     yield undefined;
                 } else {
                     const operatorShare = getRandomInteger(0, stakingPools[poolId].operatorShare).toNumber();
-                    yield assertion.executeAsync({
-                        args: [poolId, operatorShare],
-                        txData: { from: this.actor.address },
-                    });
+                    yield assertion.executeAsync([poolId, operatorShare], { from: this.actor.address });
                 }
             }
         }
diff --git a/contracts/integrations/test/framework/actors/staker.ts b/contracts/integrations/test/framework/actors/staker.ts
index 4898a4804e..b92f98475d 100644
--- a/contracts/integrations/test/framework/actors/staker.ts
+++ b/contracts/integrations/test/framework/actors/staker.ts
@@ -76,7 +76,7 @@ export function StakerMixin<TBase extends Constructor>(Base: TBase): TBase & Con
                 await balanceStore.updateErc20BalancesAsync();
                 const zrxBalance = balanceStore.balances.erc20[this.actor.address][zrx.address];
                 const amount = getRandomInteger(0, zrxBalance);
-                yield assertion.executeAsync({ args: [amount], txData: { from: this.actor.address } });
+                yield assertion.executeAsync([amount], { from: this.actor.address });
             }
         }
 
@@ -95,7 +95,7 @@ export function StakerMixin<TBase extends Constructor>(Base: TBase): TBase & Con
                     undelegatedStake.nextEpochBalance,
                 );
                 const amount = getRandomInteger(0, withdrawableStake);
-                yield assertion.executeAsync({ args: [amount], txData: { from: this.actor.address } });
+                yield assertion.executeAsync([amount], { from: this.actor.address });
             }
         }
 
@@ -124,7 +124,7 @@ export function StakerMixin<TBase extends Constructor>(Base: TBase): TBase & Con
                         : this.stake[StakeStatus.Delegated][from.poolId].nextEpochBalance;
                 const amount = getRandomInteger(0, moveableStake);
 
-                yield assertion.executeAsync({ args: [from, to, amount], txData: { from: this.actor.address } });
+                yield assertion.executeAsync([from, to, amount], { from: this.actor.address });
             }
         }
     };
diff --git a/contracts/integrations/test/framework/actors/taker.ts b/contracts/integrations/test/framework/actors/taker.ts
index 65672f9a52..ca545966cd 100644
--- a/contracts/integrations/test/framework/actors/taker.ts
+++ b/contracts/integrations/test/framework/actors/taker.ts
@@ -1,7 +1,11 @@
+import { constants, getRandomInteger } from '@0x/contracts-test-utils';
 import { SignedOrder } from '@0x/types';
 import { BigNumber } from '@0x/utils';
 import { TransactionReceiptWithDecodedLogs, TxData } from 'ethereum-types';
+import * as _ from 'lodash';
 
+import { validFillOrderCompleteFillAssertion } from '../assertions/fillOrder';
+import { AssertionResult } from '../assertions/function_assertion';
 import { DeploymentManager } from '../deployment_manager';
 
 import { Actor, Constructor } from './base';
@@ -31,6 +35,12 @@ export function TakerMixin<TBase extends Constructor>(Base: TBase): TBase & Cons
             // tslint:disable-next-line:no-inferred-empty-object-type
             super(...args);
             this.actor = (this as any) as Actor;
+
+            // Register this mixin's assertion generators
+            this.actor.simulationActions = {
+                ...this.actor.simulationActions,
+                validFillOrderCompleteFill: this._validFillOrderCompleteFill(),
+            };
         }
 
         /**
@@ -50,6 +60,37 @@ export function TakerMixin<TBase extends Constructor>(Base: TBase): TBase & Cons
                     ...txData,
                 });
         }
+
+        private async *_validFillOrderCompleteFill(): AsyncIterableIterator<AssertionResult | void> {
+            const { marketMakers } = this.actor.simulationEnvironment!;
+            const assertion = validFillOrderCompleteFillAssertion(this.actor.deployment);
+            while (true) {
+                const maker = _.sample(marketMakers);
+                if (maker === undefined) {
+                    yield undefined;
+                } else {
+                    // Configure the maker's token balances so that the order will definitely be fillable.
+                    await Promise.all([
+                        ...this.actor.deployment.tokens.erc20.map(async token => maker.configureERC20TokenAsync(token)),
+                        ...this.actor.deployment.tokens.erc20.map(async token =>
+                            this.actor.configureERC20TokenAsync(token),
+                        ),
+                        this.actor.configureERC20TokenAsync(
+                            this.actor.deployment.tokens.weth,
+                            this.actor.deployment.staking.stakingProxy.address,
+                        ),
+                    ]);
+
+                    const order = await maker.signOrderAsync({
+                        makerAssetAmount: getRandomInteger(constants.ZERO_AMOUNT, constants.INITIAL_ERC20_BALANCE),
+                        takerAssetAmount: getRandomInteger(constants.ZERO_AMOUNT, constants.INITIAL_ERC20_BALANCE),
+                    });
+                    yield assertion.executeAsync([order, order.takerAssetAmount, order.signature], {
+                        from: this.actor.address,
+                    });
+                }
+            }
+        }
     };
 }
 
diff --git a/contracts/integrations/test/framework/assertions/createStakingPool.ts b/contracts/integrations/test/framework/assertions/createStakingPool.ts
index 5f781151e8..6748b44271 100644
--- a/contracts/integrations/test/framework/assertions/createStakingPool.ts
+++ b/contracts/integrations/test/framework/assertions/createStakingPool.ts
@@ -13,6 +13,7 @@ import { FunctionAssertion, FunctionResult } from './function_assertion';
  * Returns a FunctionAssertion for `createStakingPool` which assumes valid input is provided. The
  * FunctionAssertion checks that the new poolId is one more than the last poolId.
  */
+/* tslint:disable:no-non-null-assertion */
 export function validCreateStakingPoolAssertion(
     deployment: DeploymentManager,
     pools: StakingPoolById,
@@ -34,25 +35,26 @@ export function validCreateStakingPoolAssertion(
             after: async (
                 expectedPoolId: string,
                 result: FunctionResult,
-                args: {
-                    args: [number, boolean];
-                    txData: Partial<TxData>;
-                },
+                args: [number, boolean],
+                txData: Partial<TxData>,
             ) => {
-                logUtils.log(`createStakingPool(${args.args[0]}, ${args.args[1]}) => ${expectedPoolId}`);
+                const [operatorShare, shouldAddMakerAsOperator] = args;
+
+                logUtils.log(`createStakingPool(${operatorShare}, ${shouldAddMakerAsOperator}) => ${expectedPoolId}`);
 
                 // Checks the logs for the new poolId, verifies that it is as expected
-                const log = result.receipt!.logs[0]; // tslint:disable-line:no-non-null-assertion
+                const log = result.receipt!.logs[0];
                 const actualPoolId = (log as any).args.poolId;
                 expect(actualPoolId).to.equal(expectedPoolId);
 
                 // Adds the new pool to local state
                 pools[actualPoolId] = {
-                    operator: args.txData.from as string,
-                    operatorShare: args.args[0],
+                    operator: txData.from!,
+                    operatorShare,
                     delegatedStake: new StoredBalance(),
                 };
             },
         },
     );
 }
+/* tslint:enable:no-non-null-assertion*/
diff --git a/contracts/integrations/test/framework/assertions/decreaseStakingPoolOperatorShare.ts b/contracts/integrations/test/framework/assertions/decreaseStakingPoolOperatorShare.ts
index 90ffa60c12..9a6ff1a0c4 100644
--- a/contracts/integrations/test/framework/assertions/decreaseStakingPoolOperatorShare.ts
+++ b/contracts/integrations/test/framework/assertions/decreaseStakingPoolOperatorShare.ts
@@ -1,6 +1,7 @@
 import { StakingPoolById } from '@0x/contracts-staking';
 import { expect } from '@0x/contracts-test-utils';
 import { logUtils } from '@0x/utils';
+import { TxData } from 'ethereum-types';
 
 import { DeploymentManager } from '../deployment_manager';
 
@@ -19,15 +20,15 @@ export function validDecreaseStakingPoolOperatorShareAssertion(
     return new FunctionAssertion<[string, number], {}, void>(
         stakingWrapper.decreaseStakingPoolOperatorShare.bind(stakingWrapper),
         {
-            after: async (_beforeInfo, _result: FunctionResult, args: { args: [string, number] }) => {
-                const poolId = args.args[0];
-                const expectedOperatorShare = args.args[1];
+            after: async (_beforeInfo, _result: FunctionResult, args: [string, number], txData: Partial<TxData>) => {
+                const [poolId, expectedOperatorShare] = args;
 
                 logUtils.log(`decreaseStakingPoolOperatorShare(${poolId}, ${expectedOperatorShare})`);
 
                 // Checks that the on-chain pool's operator share has been updated.
                 const { operatorShare } = await stakingWrapper.getStakingPool(poolId).callAsync();
                 expect(operatorShare).to.bignumber.equal(expectedOperatorShare);
+
                 // Updates the pool in local state.
                 pools[poolId].operatorShare = operatorShare;
             },
diff --git a/contracts/integrations/test/framework/assertions/fillOrder.ts b/contracts/integrations/test/framework/assertions/fillOrder.ts
index 1b54d628aa..cb34ed4f43 100644
--- a/contracts/integrations/test/framework/assertions/fillOrder.ts
+++ b/contracts/integrations/test/framework/assertions/fillOrder.ts
@@ -3,12 +3,12 @@ import { ExchangeEvents, ExchangeFillEventArgs } from '@0x/contracts-exchange';
 import { constants, expect, orderHashUtils, verifyEvents } from '@0x/contracts-test-utils';
 import { FillResults, Order } from '@0x/types';
 import { BigNumber, logUtils } from '@0x/utils';
-import { TransactionReceiptWithDecodedLogs } from 'ethereum-types';
+import { TransactionReceiptWithDecodedLogs, TxData } from 'ethereum-types';
 import * as _ from 'lodash';
 
 import { DeploymentManager } from '../deployment_manager';
 
-import { FunctionArguments, FunctionAssertion, FunctionResult } from './function_assertion';
+import { FunctionAssertion, FunctionResult } from './function_assertion';
 
 function verifyFillEvents(
     takerAddress: string,
@@ -68,23 +68,30 @@ function verifyFillEvents(
  * A function assertion that verifies that a complete and valid fill succeeded and emitted the correct logs.
  */
 /* tslint:disable:no-unnecessary-type-assertion */
+/* tslint:disable:no-non-null-assertion */
 export function validFillOrderCompleteFillAssertion(
     deployment: DeploymentManager,
 ): FunctionAssertion<[Order, BigNumber, string], {}, FillResults> {
     const exchange = deployment.exchange;
 
     return new FunctionAssertion<[Order, BigNumber, string], {}, FillResults>(exchange.fillOrder.bind(exchange), {
-        after: async (_beforeInfo, result: FunctionResult, args: FunctionArguments<[Order, BigNumber, string]>) => {
-            const [order] = args.args;
+        after: async (
+            _beforeInfo,
+            result: FunctionResult,
+            args: [Order, BigNumber, string],
+            txData: Partial<TxData>,
+        ) => {
+            const [order] = args;
 
             // Ensure that the tx succeeded.
             expect(result.success).to.be.true();
 
             // Ensure that the correct events were emitted.
-            verifyFillEvents(args.txData.from!, order, result.receipt!, deployment); // tslint:disable-line:no-non-null-assertion
+            verifyFillEvents(txData.from!, order, result.receipt!, deployment);
 
-            logUtils.log(`Order filled by ${args.txData.from}`);
+            logUtils.log(`Order filled by ${txData.from}`);
         },
     });
 }
+/* tslint:enable:no-non-null-assertion */
 /* tslint:enable:no-unnecessary-type-assertion */
diff --git a/contracts/integrations/test/framework/assertions/function_assertion.ts b/contracts/integrations/test/framework/assertions/function_assertion.ts
index 411ad3acf9..ff810da3f5 100644
--- a/contracts/integrations/test/framework/assertions/function_assertion.ts
+++ b/contracts/integrations/test/framework/assertions/function_assertion.ts
@@ -5,11 +5,6 @@ import * as _ from 'lodash';
 // tslint:disable:max-classes-per-file
 export type GenericContractFunction<T> = (...args: any[]) => ContractFunctionObj<T>;
 
-export interface FunctionArguments<TArgs extends any[]> {
-    args: TArgs;
-    txData: Partial<TxData>;
-}
-
 export interface FunctionResult {
     data?: any;
     success: boolean;
@@ -27,8 +22,8 @@ export interface FunctionResult {
  *              function.
  */
 export interface Condition<TArgs extends any[], TBefore> {
-    before: (args: FunctionArguments<TArgs>) => Promise<TBefore>;
-    after: (beforeInfo: TBefore, result: FunctionResult, args: FunctionArguments<TArgs>) => Promise<any>;
+    before: (args: TArgs, txData: Partial<TxData>) => Promise<TBefore>;
+    after: (beforeInfo: TBefore, result: FunctionResult, args: TArgs, txData: Partial<TxData>) => Promise<any>;
 }
 
 /**
@@ -39,7 +34,7 @@ export interface Condition<TArgs extends any[], TBefore> {
  * @param runAsync The function to execute for the assertion.
  */
 export interface Assertion<TArgs extends any[]> {
-    executeAsync: (args: FunctionArguments<TArgs>) => Promise<any>;
+    executeAsync: (args: TArgs, txData: TxData) => Promise<any>;
 }
 
 export interface AssertionResult<TBefore = unknown> {
@@ -67,10 +62,10 @@ export class FunctionAssertion<TArgs extends any[], TBefore, ReturnDataType> imp
         condition: Partial<Condition<TArgs, TBefore>> = {},
     ) {
         this.condition = {
-            before: async (args: FunctionArguments<TArgs>) => {
+            before: async (args: TArgs, txData: Partial<TxData>) => {
                 return ({} as any) as TBefore;
             },
-            after: async (beforeInfo: TBefore, result: FunctionResult, args: FunctionArguments<TArgs>) => {
+            after: async (beforeInfo: TBefore, result: FunctionResult, args: TArgs, txData: Partial<TxData>) => {
                 return ({} as any) as TBefore;
             },
             ...condition,
@@ -82,9 +77,9 @@ export class FunctionAssertion<TArgs extends any[], TBefore, ReturnDataType> imp
      * Runs the wrapped function and fails if the before or after assertions fail.
      * @param ...args The args to the contract wrapper function.
      */
-    public async executeAsync(args: FunctionArguments<TArgs>): Promise<AssertionResult<TBefore>> {
+    public async executeAsync(args: TArgs, txData: Partial<TxData>): Promise<AssertionResult<TBefore>> {
         // Call the before condition.
-        const beforeInfo = await this.condition.before(args);
+        const beforeInfo = await this.condition.before(args, txData);
 
         // Initialize the callResult so that the default success value is true.
         const callResult: FunctionResult = { success: true };
@@ -92,11 +87,11 @@ export class FunctionAssertion<TArgs extends any[], TBefore, ReturnDataType> imp
         // Try to make the call to the function. If it is successful, pass the
         // result and receipt to the after condition.
         try {
-            const functionWithArgs = this.wrapperFunction(...args.args) as ContractTxFunctionObj<ReturnDataType>;
-            callResult.data = await functionWithArgs.callAsync(args.txData);
+            const functionWithArgs = this.wrapperFunction(...args) as ContractTxFunctionObj<ReturnDataType>;
+            callResult.data = await functionWithArgs.callAsync(txData);
             callResult.receipt =
                 functionWithArgs.awaitTransactionSuccessAsync !== undefined
-                    ? await functionWithArgs.awaitTransactionSuccessAsync(args.txData) // tslint:disable-line:await-promise
+                    ? await functionWithArgs.awaitTransactionSuccessAsync(txData) // tslint:disable-line:await-promise
                     : undefined;
             // tslint:enable:await-promise
         } catch (error) {
@@ -106,7 +101,7 @@ export class FunctionAssertion<TArgs extends any[], TBefore, ReturnDataType> imp
         }
 
         // Call the after condition.
-        const afterInfo = await this.condition.after(beforeInfo, callResult, args);
+        const afterInfo = await this.condition.after(beforeInfo, callResult, args, txData);
 
         return {
             beforeInfo,
diff --git a/contracts/integrations/test/framework/assertions/joinStakingPool.ts b/contracts/integrations/test/framework/assertions/joinStakingPool.ts
index 6f9db95acd..478268ca63 100644
--- a/contracts/integrations/test/framework/assertions/joinStakingPool.ts
+++ b/contracts/integrations/test/framework/assertions/joinStakingPool.ts
@@ -1,50 +1,43 @@
 import { StakingEvents, StakingMakerStakingPoolSetEventArgs } from '@0x/contracts-staking';
 import { expect, filterLogsToArguments } from '@0x/contracts-test-utils';
 import { logUtils } from '@0x/utils';
+import { TxData } from 'ethereum-types';
 
 import { DeploymentManager } from '../deployment_manager';
 
-import { FunctionArguments, FunctionAssertion, FunctionResult } from './function_assertion';
+import { FunctionAssertion, FunctionResult } from './function_assertion';
 
 /**
  * Returns a function assertion that verifies valid pool joining.
  */
+/* tslint:disable:no-unnecessary-type-assertion */
+/* tslint:disable:no-non-null-assertion */
 export function validJoinStakingPoolAssertion(deployment: DeploymentManager): FunctionAssertion<[string], {}, void> {
     const { stakingWrapper } = deployment.staking;
 
     return new FunctionAssertion<[string], {}, void>(stakingWrapper.joinStakingPoolAsMaker.bind(stakingWrapper), {
-        after: async (_beforeInfo, _result: FunctionResult, args: FunctionArguments<[string]>) => {
-            const poolId = args.args[0];
-
-            if (args.txData === undefined) {
-                throw new Error('Undefined transaction data');
-            }
-
-            if (args.txData.from === undefined) {
-                throw new Error('Undefined from address');
-            }
-
-            if (_result.receipt === undefined) {
-                throw new Error('Undefined transaction receipt');
-            }
+        after: async (_beforeInfo, _result: FunctionResult, args: [string], txData: Partial<TxData>) => {
+            const [poolId] = args;
 
             expect(_result.success).to.be.true();
 
-            const logs = _result.receipt.logs;
+            const logs = _result.receipt!.logs;
             const logArgs = filterLogsToArguments<StakingMakerStakingPoolSetEventArgs>(
                 logs,
                 StakingEvents.MakerStakingPoolSet,
             );
             expect(logArgs).to.be.deep.eq([
                 {
-                    makerAddress: args.txData.from,
+                    makerAddress: txData.from!,
                     poolId,
                 },
             ]);
-            const joinedPoolId = await deployment.staking.stakingWrapper.poolIdByMaker(args.txData.from).callAsync();
+            const joinedPoolId = await deployment.staking.stakingWrapper.poolIdByMaker(txData.from!).callAsync();
             expect(joinedPoolId).to.be.eq(poolId);
 
-            logUtils.log(`Pool ${poolId} joined by ${args.txData.from}`); /* tslint:disable-line:no-console */
+            logUtils.log(`Pool ${poolId} joined by ${txData.from}`);
         },
     });
 }
+/* tslint:enable:no-non-null-assertion */
+/* tslint:enable:no-unnecessary-type-assertion */
diff --git a/contracts/integrations/test/framework/assertions/moveStake.ts b/contracts/integrations/test/framework/assertions/moveStake.ts
index 3b464e59dd..f65d98ab41 100644
--- a/contracts/integrations/test/framework/assertions/moveStake.ts
+++ b/contracts/integrations/test/framework/assertions/moveStake.ts
@@ -8,11 +8,12 @@ import {
 } from '@0x/contracts-staking';
 import { constants, expect } from '@0x/contracts-test-utils';
 import { BigNumber, logUtils } from '@0x/utils';
+import { TxData } from 'ethereum-types';
 import * as _ from 'lodash';
 
 import { DeploymentManager } from '../deployment_manager';
 
-import { FunctionArguments, FunctionAssertion, FunctionResult } from './function_assertion';
+import { FunctionAssertion, FunctionResult } from './function_assertion';
 
 function incrementNextEpochBalance(stakeBalance: StoredBalance, amount: BigNumber): void {
     _.update(stakeBalance, ['nextEpochBalance'], balance => (balance || constants.ZERO_AMOUNT).plus(amount));
@@ -76,6 +77,7 @@ function updateNextEpochBalances(
  * Returns a FunctionAssertion for `moveStake` which assumes valid input is provided. The
  * FunctionAssertion checks that the staker's
  */
+/* tslint:disable:no-unnecessary-type-assertion */
 export function validMoveStakeAssertion(
     deployment: DeploymentManager,
     globalStake: GlobalStakeByStatus,
@@ -90,9 +92,10 @@ export function validMoveStakeAssertion(
             after: async (
                 _beforeInfo: {},
                 _result: FunctionResult,
-                args: FunctionArguments<[StakeInfo, StakeInfo, BigNumber]>,
+                args: [StakeInfo, StakeInfo, BigNumber],
+                txData: Partial<TxData>,
             ) => {
-                const [from, to, amount] = args.args;
+                const [from, to, amount] = args;
 
                 logUtils.log(
                     `moveStake({status: ${StakeStatus[from.status]}, poolId: ${from.poolId} }, { status: ${
@@ -100,7 +103,7 @@ export function validMoveStakeAssertion(
                     }, poolId: ${to.poolId} }, ${amount})`,
                 );
 
-                const owner = args.txData.from as string;
+                const owner = txData.from!; // tslint:disable-line:no-non-null-assertion
 
                 // Update local balances to match the expected result of this `moveStake` operation
                 const updatedPools = updateNextEpochBalances(globalStake, ownerStake, pools, from, to, amount);
@@ -140,3 +143,4 @@ export function validMoveStakeAssertion(
         },
     );
 }
+/* tslint:enable:no-unnecessary-type-assertion */
diff --git a/contracts/integrations/test/framework/assertions/stake.ts b/contracts/integrations/test/framework/assertions/stake.ts
index 76c5fff406..ac88003f0c 100644
--- a/contracts/integrations/test/framework/assertions/stake.ts
+++ b/contracts/integrations/test/framework/assertions/stake.ts
@@ -1,12 +1,13 @@
 import { GlobalStakeByStatus, OwnerStakeByStatus, StakeStatus, StoredBalance } from '@0x/contracts-staking';
 import { expect } from '@0x/contracts-test-utils';
 import { BigNumber, logUtils } from '@0x/utils';
+import { TxData } from 'ethereum-types';
 
 import { BlockchainBalanceStore } from '../balances/blockchain_balance_store';
 import { LocalBalanceStore } from '../balances/local_balance_store';
 import { DeploymentManager } from '../deployment_manager';
 
-import { FunctionArguments, FunctionAssertion, FunctionResult } from './function_assertion';
+import { FunctionAssertion, FunctionResult } from './function_assertion';
 
 function expectedUndelegatedStake(
     initStake: OwnerStakeByStatus | GlobalStakeByStatus,
@@ -24,6 +25,7 @@ function expectedUndelegatedStake(
  * FunctionAssertion checks that the staker and zrxVault's balances of ZRX decrease and increase,
  * respectively, by the input amount.
  */
+/* tslint:disable:no-unnecessary-type-assertion */
 export function validStakeAssertion(
     deployment: DeploymentManager,
     balanceStore: BlockchainBalanceStore,
@@ -33,13 +35,13 @@ export function validStakeAssertion(
     const { stakingWrapper, zrxVault } = deployment.staking;
 
     return new FunctionAssertion(stakingWrapper.stake.bind(stakingWrapper), {
-        before: async (args: FunctionArguments<[BigNumber]>) => {
-            const [amount] = args.args;
+        before: async (args: [BigNumber], txData: Partial<TxData>) => {
+            const [amount] = args;
 
             // Simulates the transfer of ZRX from staker to vault
             const expectedBalances = LocalBalanceStore.create(balanceStore);
             expectedBalances.transferAsset(
-                args.txData.from as string,
+                txData.from!, // tslint:disable-line:no-non-null-assertion
                 zrxVault.address,
                 amount,
                 deployment.assetDataEncoder.ERC20Token(deployment.tokens.zrx.address).getABIEncodedTransactionData(),
@@ -49,9 +51,10 @@ export function validStakeAssertion(
         after: async (
             expectedBalances: LocalBalanceStore,
             _result: FunctionResult,
-            args: FunctionArguments<[BigNumber]>,
+            args: [BigNumber],
+            txData: Partial<TxData>,
         ) => {
-            const [amount] = args.args;
+            const [amount] = args;
 
             logUtils.log(`stake(${amount})`);
 
@@ -61,7 +64,7 @@ export function validStakeAssertion(
 
             // Checks that the owner's undelegated stake has increased by the stake amount
             const ownerUndelegatedStake = await stakingWrapper
-                .getOwnerStakeByStatus(args.txData.from as string, StakeStatus.Undelegated)
+                .getOwnerStakeByStatus(txData.from!, StakeStatus.Undelegated) // tslint:disable-line:no-non-null-assertion
                 .callAsync();
             const expectedOwnerUndelegatedStake = expectedUndelegatedStake(ownerStake, amount);
             expect(ownerUndelegatedStake, 'Owner undelegated stake').to.deep.equal(expectedOwnerUndelegatedStake);
@@ -79,3 +82,4 @@ export function validStakeAssertion(
         },
     });
 }
+/* tslint:enable:no-unnecessary-type-assertion */
diff --git a/contracts/integrations/test/framework/assertions/unstake.ts b/contracts/integrations/test/framework/assertions/unstake.ts
index 4308160b7e..6bfc6363fe 100644
--- a/contracts/integrations/test/framework/assertions/unstake.ts
+++ b/contracts/integrations/test/framework/assertions/unstake.ts
@@ -1,12 +1,13 @@
 import { GlobalStakeByStatus, OwnerStakeByStatus, StakeStatus, StoredBalance } from '@0x/contracts-staking';
 import { expect } from '@0x/contracts-test-utils';
 import { BigNumber, logUtils } from '@0x/utils';
+import { TxData } from 'ethereum-types';
 
 import { BlockchainBalanceStore } from '../balances/blockchain_balance_store';
 import { LocalBalanceStore } from '../balances/local_balance_store';
 import { DeploymentManager } from '../deployment_manager';
 
-import { FunctionArguments, FunctionAssertion, FunctionResult } from './function_assertion';
+import { FunctionAssertion, FunctionResult } from './function_assertion';
 
 function expectedUndelegatedStake(
     initStake: OwnerStakeByStatus | GlobalStakeByStatus,
@@ -24,6 +25,8 @@ function expectedUndelegatedStake(
  * FunctionAssertion checks that the staker and zrxVault's balances of ZRX increase and decrease,
  * respectively, by the input amount.
  */
+/* tslint:disable:no-unnecessary-type-assertion */
+/* tslint:disable:no-non-null-assertion */
 export function validUnstakeAssertion(
     deployment: DeploymentManager,
     balanceStore: BlockchainBalanceStore,
@@ -33,14 +36,14 @@ export function validUnstakeAssertion(
     const { stakingWrapper, zrxVault } = deployment.staking;
 
     return new FunctionAssertion(stakingWrapper.unstake.bind(stakingWrapper), {
-        before: async (args: FunctionArguments<[BigNumber]>) => {
-            const [amount] = args.args;
+        before: async (args: [BigNumber], txData: Partial<TxData>) => {
+            const [amount] = args;
 
             // Simulates the transfer of ZRX from vault to staker
             const expectedBalances = LocalBalanceStore.create(balanceStore);
             expectedBalances.transferAsset(
                 zrxVault.address,
-                args.txData.from as string,
+                txData.from!,
                 amount,
                 deployment.assetDataEncoder.ERC20Token(deployment.tokens.zrx.address).getABIEncodedTransactionData(),
             );
@@ -49,9 +52,10 @@ export function validUnstakeAssertion(
         after: async (
             expectedBalances: LocalBalanceStore,
             _result: FunctionResult,
-            args: FunctionArguments<[BigNumber]>,
+            args: [BigNumber],
+            txData: Partial<TxData>,
         ) => {
-            const [amount] = args.args;
+            const [amount] = args;
 
             logUtils.log(`unstake(${amount})`);
 
@@ -61,7 +65,7 @@ export function validUnstakeAssertion(
 
             // Checks that the owner's undelegated stake has decreased by the stake amount
             const ownerUndelegatedStake = await stakingWrapper
-                .getOwnerStakeByStatus(args.txData.from as string, StakeStatus.Undelegated)
+                .getOwnerStakeByStatus(txData.from!, StakeStatus.Undelegated)
                 .callAsync();
             const expectedOwnerUndelegatedStake = expectedUndelegatedStake(ownerStake, amount);
             expect(ownerUndelegatedStake, 'Owner undelegated stake').to.deep.equal(expectedOwnerUndelegatedStake);
@@ -79,3 +83,5 @@ export function validUnstakeAssertion(
         },
     });
 }
+/* tslint:enable:no-non-null-assertion */
+/* tslint:enable:no-unnecessary-type-assertion */
diff --git a/contracts/integrations/test/framework/tests/function_assertion_test.ts b/contracts/integrations/test/framework/tests/function_assertion_test.ts
index 72664611a6..9e9e746b46 100644
--- a/contracts/integrations/test/framework/tests/function_assertion_test.ts
+++ b/contracts/integrations/test/framework/tests/function_assertion_test.ts
@@ -1,10 +1,10 @@
 import { blockchainTests, constants, expect, filterLogsToArguments, getRandomInteger } from '@0x/contracts-test-utils';
 import { BigNumber, StringRevertError } from '@0x/utils';
-import { TransactionReceiptWithDecodedLogs } from 'ethereum-types';
+import { TransactionReceiptWithDecodedLogs, TxData } from 'ethereum-types';
 
 import { artifacts } from '../../artifacts';
 import { TestFrameworkContract, TestFrameworkEventEventArgs, TestFrameworkEvents } from '../../wrappers';
-import { FunctionArguments, FunctionAssertion, FunctionResult } from '../assertions/function_assertion';
+import { FunctionAssertion, FunctionResult } from '../assertions/function_assertion';
 
 const { ZERO_AMOUNT, MAX_UINT256 } = constants;
 
@@ -26,13 +26,13 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             const assertion = new FunctionAssertion<[BigNumber], void, BigNumber>(
                 exampleContract.returnInteger.bind(exampleContract),
                 {
-                    before: async (args: { args: [BigNumber] }) => {
+                    before: async (args: [BigNumber], txData: Partial<TxData>) => {
                         sideEffectTarget = randomInput;
                     },
                 },
             );
             const randomInput = getRandomInteger(ZERO_AMOUNT, MAX_UINT256);
-            await assertion.executeAsync({ args: [randomInput], txData: {} });
+            await assertion.executeAsync([randomInput], {});
             expect(sideEffectTarget).bignumber.to.be.eq(randomInput);
         });
 
@@ -41,19 +41,24 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             const assertion = new FunctionAssertion<[BigNumber], void, BigNumber>(
                 exampleContract.returnInteger.bind(exampleContract),
                 {
-                    after: async (_beforeInfo: any, _result: FunctionResult, args: FunctionArguments<[BigNumber]>) => {
-                        sideEffectTarget = args.args[0];
+                    after: async (
+                        _beforeInfo: any,
+                        _result: FunctionResult,
+                        args: [BigNumber],
+                        txData: Partial<TxData>,
+                    ) => {
+                        [sideEffectTarget] = args;
                     },
                 },
             );
             const randomInput = getRandomInteger(ZERO_AMOUNT, MAX_UINT256);
-            await assertion.executeAsync({ args: [randomInput], txData: {} });
+            await assertion.executeAsync([randomInput], {});
             expect(sideEffectTarget).bignumber.to.be.eq(randomInput);
         });
 
         it('should not fail immediately if the wrapped function fails', async () => {
             const assertion = new FunctionAssertion<[], {}, void>(exampleContract.emptyRevert.bind(exampleContract));
-            await assertion.executeAsync({ args: [], txData: {} });
+            await assertion.executeAsync([], {});
         });
 
         it('should pass the return value of "before" to "after"', async () => {
@@ -62,15 +67,20 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             const assertion = new FunctionAssertion<[BigNumber], BigNumber, BigNumber>(
                 exampleContract.returnInteger.bind(exampleContract),
                 {
-                    before: async (_args: FunctionArguments<[BigNumber]>) => {
+                    before: async (_args: [BigNumber], _txData: Partial<TxData>) => {
                         return randomInput;
                     },
-                    after: async (beforeInfo: any, _result: FunctionResult, _args: FunctionArguments<[BigNumber]>) => {
+                    after: async (
+                        beforeInfo: any,
+                        _result: FunctionResult,
+                        _args: [BigNumber],
+                        _txData: Partial<TxData>,
+                    ) => {
                         sideEffectTarget = beforeInfo;
                     },
                 },
             );
-            await assertion.executeAsync({ args: [randomInput], txData: {} });
+            await assertion.executeAsync([randomInput], {});
             expect(sideEffectTarget).bignumber.to.be.eq(randomInput);
         });
 
@@ -79,13 +89,18 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             const assertion = new FunctionAssertion<[BigNumber], void, BigNumber>(
                 exampleContract.returnInteger.bind(exampleContract),
                 {
-                    after: async (_beforeInfo: any, result: FunctionResult, _args: FunctionArguments<[BigNumber]>) => {
+                    after: async (
+                        _beforeInfo: any,
+                        result: FunctionResult,
+                        _args: [BigNumber],
+                        _txData: Partial<TxData>,
+                    ) => {
                         sideEffectTarget = result.data;
                     },
                 },
             );
             const randomInput = getRandomInteger(ZERO_AMOUNT, MAX_UINT256);
-            await assertion.executeAsync({ args: [randomInput], txData: {} });
+            await assertion.executeAsync([randomInput], {});
             expect(sideEffectTarget).bignumber.to.be.eq(randomInput);
         });
 
@@ -94,7 +109,12 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             const assertion = new FunctionAssertion<[string], void, void>(
                 exampleContract.emitEvent.bind(exampleContract),
                 {
-                    after: async (_beforeInfo: any, result: FunctionResult, _args: FunctionArguments<[string]>) => {
+                    after: async (
+                        _beforeInfo: any,
+                        result: FunctionResult,
+                        _args: [string],
+                        _txData: Partial<TxData>,
+                    ) => {
                         if (result.receipt) {
                             sideEffectTarget = result.receipt;
                         }
@@ -103,7 +123,7 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             );
 
             const input = 'emitted data';
-            await assertion.executeAsync({ args: [input], txData: {} });
+            await assertion.executeAsync([input], {});
 
             // Ensure that the correct events were emitted.
             const [event] = filterLogsToArguments<TestFrameworkEventEventArgs>(
@@ -118,13 +138,18 @@ blockchainTests.resets('FunctionAssertion Unit Tests', env => {
             const assertion = new FunctionAssertion<[string], void, void>(
                 exampleContract.stringRevert.bind(exampleContract),
                 {
-                    after: async (_beforeInfo: any, result: FunctionResult, _args: FunctionArguments<[string]>) => {
+                    after: async (
+                        _beforeInfo: any,
+                        result: FunctionResult,
+                        _args: [string],
+                        _txData: Partial<TxData>,
+                    ) => {
                         sideEffectTarget = result.data;
                     },
                 },
             );
             const message = 'error message';
-            await assertion.executeAsync({ args: [message], txData: {} });
+            await assertion.executeAsync([message], {});
 
             const expectedError = new StringRevertError(message);
             return expect(Promise.reject(sideEffectTarget!)).to.revertWith(expectedError); // tslint:disable-line
diff --git a/contracts/integrations/test/fuzz_tests/pool_membership_test.ts b/contracts/integrations/test/fuzz_tests/pool_membership_test.ts
index edce353084..00670f18d9 100644
--- a/contracts/integrations/test/fuzz_tests/pool_membership_test.ts
+++ b/contracts/integrations/test/fuzz_tests/pool_membership_test.ts
@@ -1,24 +1,22 @@
 import { blockchainTests, constants } from '@0x/contracts-test-utils';
 import * as _ from 'lodash';
 
+import { MakerTaker } from '../framework/actors/hybrids';
 import { Maker } from '../framework/actors/maker';
-import { PoolMember } from '../framework/actors/pool_member';
 import { AssertionResult } from '../framework/assertions/function_assertion';
 import { BlockchainBalanceStore } from '../framework/balances/blockchain_balance_store';
 import { DeploymentManager } from '../framework/deployment_manager';
 import { Simulation, SimulationEnvironment } from '../framework/simulation';
 
 import { PoolManagementSimulation } from './pool_management_test';
-import { StakeManagementSimulation } from './stake_management_test';
 
 class PoolMembershipSimulation extends Simulation {
     protected async *_assertionGenerator(): AsyncIterableIterator<AssertionResult | void> {
         const { deployment } = this.environment;
 
         const poolManagement = new PoolManagementSimulation(this.environment);
-        const stakeManagement = new StakeManagementSimulation(this.environment);
 
-        const member = new PoolMember({
+        const member = new MakerTaker({
             name: 'member',
             deployment,
             simulationEnvironment: this.environment,
@@ -28,7 +26,6 @@ class PoolMembershipSimulation extends Simulation {
             member.simulationActions.validJoinStakingPool,
             member.simulationActions.validFillOrderCompleteFill,
             poolManagement.generator,
-            stakeManagement.generator,
         ];
 
         while (true) {
@@ -38,7 +35,7 @@ class PoolMembershipSimulation extends Simulation {
     }
 }
 
-blockchainTests.only('pool membership fuzz test', env => {
+blockchainTests.skip('pool membership fuzz test', env => {
     let deployment: DeploymentManager;
     let maker: Maker;