From 4734acbe61d6961ee95dce138e13fee5ecd6a149 Mon Sep 17 00:00:00 2001
From: Lawrence Forman <lawrence@0xproject.com>
Date: Wed, 26 Jun 2019 15:46:39 -0400
Subject: [PATCH] `@0x/contracts-test-utils`: Add `hexConcat()` in
 `hex_utils.ts`.

---
 contracts/test-utils/CHANGELOG.json   | 4 ++++
 contracts/test-utils/src/hex_utils.ts | 8 ++++++++
 contracts/test-utils/src/index.ts     | 1 +
 3 files changed, 13 insertions(+)
 create mode 100644 contracts/test-utils/src/hex_utils.ts

diff --git a/contracts/test-utils/CHANGELOG.json b/contracts/test-utils/CHANGELOG.json
index 03327c5a1c..e90a09bbbe 100644
--- a/contracts/test-utils/CHANGELOG.json
+++ b/contracts/test-utils/CHANGELOG.json
@@ -29,6 +29,10 @@
             {
                 "note": "Remove formatters",
                 "pr": 1834
+            },
+            {
+                "note": "Add `hexConcat()` in `hex_utils.ts`",
+                "pr": 1885
             }
         ]
     },
diff --git a/contracts/test-utils/src/hex_utils.ts b/contracts/test-utils/src/hex_utils.ts
new file mode 100644
index 0000000000..95c2435b1f
--- /dev/null
+++ b/contracts/test-utils/src/hex_utils.ts
@@ -0,0 +1,8 @@
+import * as ethUtil from 'ethereumjs-util';
+
+/**
+ * Concatenate all arguments as a hex string.
+ */
+export function hexConcat(...args: Array<string | number | Buffer>): string {
+    return ethUtil.bufferToHex(Buffer.concat(args.map(h => ethUtil.toBuffer(h))));
+}
diff --git a/contracts/test-utils/src/index.ts b/contracts/test-utils/src/index.ts
index f98a6309f8..44c101adcc 100644
--- a/contracts/test-utils/src/index.ts
+++ b/contracts/test-utils/src/index.ts
@@ -27,6 +27,7 @@ export { OrderFactory } from './order_factory';
 export { bytes32Values, testCombinatoriallyWithReferenceFuncAsync, uint256Values } from './combinatorial_utils';
 export { TransactionFactory } from './transaction_factory';
 export { testWithReferenceFuncAsync } from './test_with_reference';
+export { hexConcat } from './hex_utils';
 export {
     ContractName,
     ERC20BalancesByOwner,