diff --git a/test/constants.js b/test/constants.js
index b1708e9..a85c63b 100644
--- a/test/constants.js
+++ b/test/constants.js
@@ -2,8 +2,8 @@
 // SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
 // Code is Apache-2.0 and docs are CC-BY-4.0
 
-import test from 'ava'
 import base58 from 'bs58'
+import { createHash } from 'crypto'
 import { Ed25519Sha256 } from 'crypto-conditions'
 import { Transaction, Ed25519Keypair } from '../src'
 // TODO: Find out if ava has something like conftest, if so put this there.
@@ -34,20 +34,19 @@ export const bobCondition = Transaction.makeEd25519Condition(bob.publicKey)
 export const bobOutput = Transaction.makeOutput(bobCondition)
 
 export function delegatedSignTransaction(...keyPairs) {
-    return function sign(input, transactionHash) {
+    return function sign(serializedTransaction, input, index) {
+        const transactionUniqueFulfillment = input.fulfills ? serializedTransaction
+        .concat(input.fulfills.transaction_id)
+        .concat(input.fulfills.output_index) : serializedTransaction
+        const transactionHash = createHash('sha3-256').update(transactionUniqueFulfillment).digest()
         const filteredKeyPairs = keyPairs.filter(({ publicKey }) =>
             input.owners_before.includes(publicKey))
+
         const ed25519Fulfillment = new Ed25519Sha256()
         filteredKeyPairs.forEach(keyPair => {
             const privateKey = Buffer.from(base58.decode(keyPair.privateKey))
-            ed25519Fulfillment.sign(
-                Buffer.from(transactionHash, 'hex'),
-                privateKey
-            )
+            ed25519Fulfillment.sign(transactionHash, privateKey)
         })
         return ed25519Fulfillment.serializeUri()
     }
 }
-
-// TODO: https://github.com/avajs/ava/issues/1190
-test('', () => 'dirty hack. TODO: Exclude this file from being run by ava')