Only send in amountAvailableToFill if it's a non-zero amount, add additional tests and nest, and put error into its own file

4 files changed, 25 insertions, 21 deletions

diff --git a/packages/asset-buyer/src/errors.ts b/packages/asset-buyer/src/errors.ts
new file mode 100644
index 000000000..ef05a5d0a
--- /dev/null
+++ b/packages/asset-buyer/src/errors.ts
@@ -0,0 +1,16 @@
+import { BigNumber } from '@0x/utils';
+
+import { AssetBuyerError } from './types';
+
+/**
+ * Error class representing insufficient asset liquidity
+ */
+export class InsufficientAssetLiquidityError extends Error {
+    public amountAvailableToFill?: BigNumber;
+    constructor(amountAvailableToFill?: BigNumber) {
+        super(AssetBuyerError.InsufficientAssetLiquidity);
+        this.amountAvailableToFill = amountAvailableToFill;
+        // Setting prototype so instanceof works.  See https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work
+        Object.setPrototypeOf(this, InsufficientAssetLiquidityError.prototype);
+    }
+}
diff --git a/packages/asset-buyer/src/index.ts b/packages/asset-buyer/src/index.ts
index 59515e24f..a42d7e272 100644
--- a/packages/asset-buyer/src/index.ts
+++ b/packages/asset-buyer/src/index.ts
@@ -9,6 +9,7 @@ export { SignedOrder } from '@0x/types';
 export { BigNumber } from '@0x/utils';
 
 export { AssetBuyer } from './asset_buyer';
+export { InsufficientAssetLiquidityError } from './errors';
 export { BasicOrderProvider } from './order_providers/basic_order_provider';
 export { StandardRelayerAPIOrderProvider } from './order_providers/standard_relayer_api_order_provider';
 export {
@@ -18,7 +19,6 @@ export {
     BuyQuoteExecutionOpts,
     BuyQuoteInfo,
     BuyQuoteRequestOpts,
-    InsufficientAssetLiquidityError,
     OrderProvider,
     OrderProviderRequest,
     OrderProviderResponse,
diff --git a/packages/asset-buyer/src/types.ts b/packages/asset-buyer/src/types.ts
index d435f337e..d5d6be695 100644
--- a/packages/asset-buyer/src/types.ts
+++ b/packages/asset-buyer/src/types.ts
@@ -102,7 +102,7 @@ export interface AssetBuyerOpts {
 }
 
 /**
- * Possible errors thrown by an AssetBuyer instance or associated static methods.
+ * Possible error messages thrown by an AssetBuyer instance or associated static methods.
  */
 export enum AssetBuyerError {
     NoEtherTokenContractFound = 'NO_ETHER_TOKEN_CONTRACT_FOUND',
@@ -117,16 +117,6 @@ export enum AssetBuyerError {
     TransactionValueTooLow = 'TRANSACTION_VALUE_TOO_LOW',
 }
 
-export class InsufficientAssetLiquidityError extends Error {
-    public amountAvailableToFill: BigNumber;
-    constructor(amountAvailableToFill: BigNumber) {
-        super(AssetBuyerError.InsufficientAssetLiquidity);
-        this.amountAvailableToFill = amountAvailableToFill;
-        // Setting prototype so instanceof works.  See https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work
-        Object.setPrototypeOf(this, InsufficientAssetLiquidityError.prototype);
-    }
-}
-
 export interface OrdersAndFillableAmounts {
     orders: SignedOrder[];
     remainingFillableMakerAssetAmounts: BigNumber[];
diff --git a/packages/asset-buyer/src/utils/buy_quote_calculator.ts b/packages/asset-buyer/src/utils/buy_quote_calculator.ts
index 23d3e9b24..59293d1b7 100644
--- a/packages/asset-buyer/src/utils/buy_quote_calculator.ts
+++ b/packages/asset-buyer/src/utils/buy_quote_calculator.ts
@@ -1,16 +1,10 @@
 import { marketUtils, SignedOrder } from '@0x/order-utils';
 import { BigNumber } from '@0x/utils';
-import { Web3Wrapper } from '@0x/web3-wrapper';
 import * as _ from 'lodash';
 
 import { constants } from '../constants';
-import {
-    AssetBuyerError,
-    BuyQuote,
-    BuyQuoteInfo,
-    InsufficientAssetLiquidityError,
-    OrdersAndFillableAmounts,
-} from '../types';
+import { InsufficientAssetLiquidityError } from '../errors';
+import { AssetBuyerError, BuyQuote, BuyQuoteInfo, OrdersAndFillableAmounts } from '../types';
 
 import { orderUtils } from './order_utils';
 
@@ -53,7 +47,11 @@ export const buyQuoteCalculator = {
                 .div(multiplerNeededWithSlippage)
                 .round(0, BigNumber.ROUND_DOWN);
 
-            throw new InsufficientAssetLiquidityError(amountAvailableToFillConsideringSlippage);
+            throw new InsufficientAssetLiquidityError(
+                amountAvailableToFillConsideringSlippage.gt(constants.ZERO_AMOUNT)
+                    ? amountAvailableToFillConsideringSlippage
+                    : undefined,
+            );
         }
         // if we are not buying ZRX:
         // given the orders calculated above, find the fee-orders that cover the desired assetBuyAmount (with slippage)