Add combinatorial tests for internal Exchange functions (#807)

* WIP add combinatorial tests for internal Exchange functions

* Change combinitorial testing strategy based on feedback

* Check value of filled[orderHash] in updateFilledState tests

* Add combinatorial tests for addFillResults

* Add combinatorial tests for getPartialAmount

* Implement generic `testWithReferenceFuncAsync`

* Implement generic `testCombinatoriallyWithReferenceFuncAsync`

* Add combinatorial tests for isRoundingError

* Add combinatorial tests for calculateFillResults

* Add support for Geth in internal contract tests

* Fix contract artifacts

* Change DECIMAL_PLACES to 78 and add a note.

* Document new functions in utils

* Optimize tests by only reseting state when needed

* Rename/move some files

* Print parameter names on failure in testWithReferenceFuncAsync

* Add to changelog for utils package

* Appease various linters

* Rename some more things related to FillOrderCombinatorialUtils

* Remove .only from test/exchange/internal.ts

* Remove old test for isRoundingError and getPartialAmount

* Appease linters again

* Remove old todos

* Fix typos, add comments, rename some things

* Re-add some LibMath tests

* Update contract internal tests to use new SafeMath revert reasons

* Apply PR feedback from Amir

* Apply PR feedback from Remco

* Re-add networks to ZRXToken artifact

* Remove duplicate Whitelist in compiler.json

1 files changed, 305 insertions, 0 deletions

diff --git a/packages/contracts/test/exchange/internal.ts b/packages/contracts/test/exchange/internal.ts
new file mode 100644
index 000000000..67d1d2d2c
--- /dev/null
+++ b/packages/contracts/test/exchange/internal.ts
@@ -0,0 +1,305 @@
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { Order, RevertReason, SignedOrder } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+import { TestExchangeInternalsContract } from '../../generated_contract_wrappers/test_exchange_internals';
+import { artifacts } from '../utils/artifacts';
+import {
+    getInvalidOpcodeErrorMessageForCallAsync,
+    getRevertReasonOrErrorMessageForSendTransactionAsync,
+} from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { bytes32Values, testCombinatoriallyWithReferenceFuncAsync, uint256Values } from '../utils/combinatorial_utils';
+import { constants } from '../utils/constants';
+import { FillResults } from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
+
+chaiSetup.configure();
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+const MAX_UINT256 = new BigNumber(2).pow(256).minus(1);
+
+const emptyOrder: Order = {
+    senderAddress: constants.NULL_ADDRESS,
+    makerAddress: constants.NULL_ADDRESS,
+    takerAddress: constants.NULL_ADDRESS,
+    makerFee: new BigNumber(0),
+    takerFee: new BigNumber(0),
+    makerAssetAmount: new BigNumber(0),
+    takerAssetAmount: new BigNumber(0),
+    makerAssetData: '0x',
+    takerAssetData: '0x',
+    salt: new BigNumber(0),
+    exchangeAddress: constants.NULL_ADDRESS,
+    feeRecipientAddress: constants.NULL_ADDRESS,
+    expirationTimeSeconds: new BigNumber(0),
+};
+
+const emptySignedOrder: SignedOrder = {
+    ...emptyOrder,
+    signature: '',
+};
+
+const overflowErrorForCall = new Error(RevertReason.Uint256Overflow);
+
+async function referenceGetPartialAmountAsync(
+    numerator: BigNumber,
+    denominator: BigNumber,
+    target: BigNumber,
+): Promise<BigNumber> {
+    const invalidOpcodeErrorForCall = new Error(await getInvalidOpcodeErrorMessageForCallAsync());
+    const product = numerator.mul(target);
+    if (product.greaterThan(MAX_UINT256)) {
+        throw overflowErrorForCall;
+    }
+    if (denominator.eq(0)) {
+        throw invalidOpcodeErrorForCall;
+    }
+    return product.dividedToIntegerBy(denominator);
+}
+
+describe('Exchange core internal functions', () => {
+    let testExchange: TestExchangeInternalsContract;
+    let invalidOpcodeErrorForCall: Error | undefined;
+    let overflowErrorForSendTransaction: Error | undefined;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        testExchange = await TestExchangeInternalsContract.deployFrom0xArtifactAsync(
+            artifacts.TestExchangeInternals,
+            provider,
+            txDefaults,
+        );
+        overflowErrorForSendTransaction = new Error(
+            await getRevertReasonOrErrorMessageForSendTransactionAsync(RevertReason.Uint256Overflow),
+        );
+        invalidOpcodeErrorForCall = new Error(await getInvalidOpcodeErrorMessageForCallAsync());
+    });
+    // Note(albrow): Don't forget to add beforeEach and afterEach calls to reset
+    // the blockchain state for any tests which modify it!
+
+    describe('addFillResults', async () => {
+        function makeFillResults(value: BigNumber): FillResults {
+            return {
+                makerAssetFilledAmount: value,
+                takerAssetFilledAmount: value,
+                makerFeePaid: value,
+                takerFeePaid: value,
+            };
+        }
+        async function referenceAddFillResultsAsync(
+            totalValue: BigNumber,
+            singleValue: BigNumber,
+        ): Promise<FillResults> {
+            // Note(albrow): Here, each of totalFillResults and
+            // singleFillResults will consist of fields with the same values.
+            // This should be safe because none of the fields in a given
+            // FillResults are ever used together in a mathemetical operation.
+            // They are only used with the corresponding field from *the other*
+            // FillResults, which are different.
+            const totalFillResults = makeFillResults(totalValue);
+            const singleFillResults = makeFillResults(singleValue);
+            // HACK(albrow): _.mergeWith mutates the first argument! To
+            // workaround this we use _.cloneDeep.
+            return _.mergeWith(
+                _.cloneDeep(totalFillResults),
+                singleFillResults,
+                (totalVal: BigNumber, singleVal: BigNumber) => {
+                    const newTotal = totalVal.add(singleVal);
+                    if (newTotal.greaterThan(MAX_UINT256)) {
+                        throw overflowErrorForCall;
+                    }
+                    return newTotal;
+                },
+            );
+        }
+        async function testAddFillResultsAsync(totalValue: BigNumber, singleValue: BigNumber): Promise<FillResults> {
+            const totalFillResults = makeFillResults(totalValue);
+            const singleFillResults = makeFillResults(singleValue);
+            return testExchange.publicAddFillResults.callAsync(totalFillResults, singleFillResults);
+        }
+        await testCombinatoriallyWithReferenceFuncAsync(
+            'addFillResults',
+            referenceAddFillResultsAsync,
+            testAddFillResultsAsync,
+            [uint256Values, uint256Values],
+        );
+    });
+
+    describe('calculateFillResults', async () => {
+        function makeOrder(
+            makerAssetAmount: BigNumber,
+            takerAssetAmount: BigNumber,
+            makerFee: BigNumber,
+            takerFee: BigNumber,
+        ): Order {
+            return {
+                ...emptyOrder,
+                makerAssetAmount,
+                takerAssetAmount,
+                makerFee,
+                takerFee,
+            };
+        }
+        async function referenceCalculateFillResultsAsync(
+            orderTakerAssetAmount: BigNumber,
+            takerAssetFilledAmount: BigNumber,
+            otherAmount: BigNumber,
+        ): Promise<FillResults> {
+            // Note(albrow): Here we are re-using the same value (otherAmount)
+            // for order.makerAssetAmount, order.makerFee, and order.takerFee.
+            // This should be safe because they are never used with each other
+            // in any mathematical operation in either the reference TypeScript
+            // implementation or the Solidity implementation of
+            // calculateFillResults.
+            return {
+                makerAssetFilledAmount: await referenceGetPartialAmountAsync(
+                    takerAssetFilledAmount,
+                    orderTakerAssetAmount,
+                    otherAmount,
+                ),
+                takerAssetFilledAmount,
+                makerFeePaid: await referenceGetPartialAmountAsync(
+                    takerAssetFilledAmount,
+                    orderTakerAssetAmount,
+                    otherAmount,
+                ),
+                takerFeePaid: await referenceGetPartialAmountAsync(
+                    takerAssetFilledAmount,
+                    orderTakerAssetAmount,
+                    otherAmount,
+                ),
+            };
+        }
+        async function testCalculateFillResultsAsync(
+            orderTakerAssetAmount: BigNumber,
+            takerAssetFilledAmount: BigNumber,
+            otherAmount: BigNumber,
+        ): Promise<FillResults> {
+            const order = makeOrder(otherAmount, orderTakerAssetAmount, otherAmount, otherAmount);
+            return testExchange.publicCalculateFillResults.callAsync(order, takerAssetFilledAmount);
+        }
+        await testCombinatoriallyWithReferenceFuncAsync(
+            'calculateFillResults',
+            referenceCalculateFillResultsAsync,
+            testCalculateFillResultsAsync,
+            [uint256Values, uint256Values, uint256Values],
+        );
+    });
+
+    describe('getPartialAmount', async () => {
+        async function testGetPartialAmountAsync(
+            numerator: BigNumber,
+            denominator: BigNumber,
+            target: BigNumber,
+        ): Promise<BigNumber> {
+            return testExchange.publicGetPartialAmount.callAsync(numerator, denominator, target);
+        }
+        await testCombinatoriallyWithReferenceFuncAsync(
+            'getPartialAmount',
+            referenceGetPartialAmountAsync,
+            testGetPartialAmountAsync,
+            [uint256Values, uint256Values, uint256Values],
+        );
+    });
+
+    describe('isRoundingError', async () => {
+        async function referenceIsRoundingErrorAsync(
+            numerator: BigNumber,
+            denominator: BigNumber,
+            target: BigNumber,
+        ): Promise<boolean> {
+            const product = numerator.mul(target);
+            if (denominator.eq(0)) {
+                throw invalidOpcodeErrorForCall;
+            }
+            const remainder = product.mod(denominator);
+            if (remainder.eq(0)) {
+                return false;
+            }
+            if (product.greaterThan(MAX_UINT256)) {
+                throw overflowErrorForCall;
+            }
+            if (product.eq(0)) {
+                throw invalidOpcodeErrorForCall;
+            }
+            const remainderTimes1000000 = remainder.mul('1000000');
+            if (remainderTimes1000000.greaterThan(MAX_UINT256)) {
+                throw overflowErrorForCall;
+            }
+            const errPercentageTimes1000000 = remainderTimes1000000.dividedToIntegerBy(product);
+            return errPercentageTimes1000000.greaterThan('1000');
+        }
+        async function testIsRoundingErrorAsync(
+            numerator: BigNumber,
+            denominator: BigNumber,
+            target: BigNumber,
+        ): Promise<boolean> {
+            return testExchange.publicIsRoundingError.callAsync(numerator, denominator, target);
+        }
+        await testCombinatoriallyWithReferenceFuncAsync(
+            'isRoundingError',
+            referenceIsRoundingErrorAsync,
+            testIsRoundingErrorAsync,
+            [uint256Values, uint256Values, uint256Values],
+        );
+    });
+
+    describe('updateFilledState', async () => {
+        // Note(albrow): Since updateFilledState modifies the state by calling
+        // sendTransaction, we must reset the state after each test.
+        beforeEach(async () => {
+            await blockchainLifecycle.startAsync();
+        });
+        afterEach(async () => {
+            await blockchainLifecycle.revertAsync();
+        });
+        async function referenceUpdateFilledStateAsync(
+            takerAssetFilledAmount: BigNumber,
+            orderTakerAssetFilledAmount: BigNumber,
+            // tslint:disable-next-line:no-unused-variable
+            orderHash: string,
+        ): Promise<BigNumber> {
+            const totalFilledAmount = takerAssetFilledAmount.add(orderTakerAssetFilledAmount);
+            if (totalFilledAmount.greaterThan(MAX_UINT256)) {
+                throw overflowErrorForSendTransaction;
+            }
+            return totalFilledAmount;
+        }
+        async function testUpdateFilledStateAsync(
+            takerAssetFilledAmount: BigNumber,
+            orderTakerAssetFilledAmount: BigNumber,
+            orderHash: string,
+        ): Promise<BigNumber> {
+            const fillResults = {
+                makerAssetFilledAmount: new BigNumber(0),
+                takerAssetFilledAmount,
+                makerFeePaid: new BigNumber(0),
+                takerFeePaid: new BigNumber(0),
+            };
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await testExchange.publicUpdateFilledState.sendTransactionAsync(
+                    emptySignedOrder,
+                    constants.NULL_ADDRESS,
+                    orderHash,
+                    orderTakerAssetFilledAmount,
+                    fillResults,
+                ),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            return testExchange.filled.callAsync(orderHash);
+        }
+        await testCombinatoriallyWithReferenceFuncAsync(
+            'updateFilledState',
+            referenceUpdateFilledStateAsync,
+            testUpdateFilledStateAsync,
+            [uint256Values, uint256Values, bytes32Values],
+        );
+    });
+});