Fix for endianness of contract hash (#119)

* Fixed endianness of contract hash.

* Changed 'describe.only' to 'describe' in script.spec.ts to allow all tests to run

Author: Randy808

src/issuance.js

@@ -89,10 +89,7 @@ function hashContract(contract) {
     (obj, key) => ({ ...obj, [key]: contract[key] }),
     {},
   );
-  return bcrypto
-    .sha256(Buffer.from(JSON.stringify(sortedContract)))
-    .slice()
-    .reverse();
+  return bcrypto.sha256(Buffer.from(JSON.stringify(sortedContract)));
 }
 exports.hashContract = hashContract;
 /**

test/issuance.spec.ts

@@ -312,7 +312,7 @@ describe('Issuance', () => {
         it(`should calculate the correct contract hash for ${contractFixture.contractJSON.name}`, () => {
           const computed = issuance.hashContract(contractFixture.contractJSON);
           assert.strictEqual(
-            computed.toString('hex'),
+            computed.reverse().toString('hex'),
             contractFixture.contractHash,
           );
         });

test/script.spec.ts

@@ -2,7 +2,7 @@ import * as assert from 'assert';
 import { describe, it } from 'mocha';
 import { script } from '../ts_src';
 
-describe.only('script', () => {
+describe('script', () => {
   describe('toASM', () => {
     it('converts OP_CHECKLOCKTIMEVERIFY correctly', () => {
       const asm = 'OP_CHECKLOCKTIMEVERIFY';

ts_src/issuance.ts

@@ -72,10 +72,7 @@ export function hashContract(contract: IssuanceContract): Buffer {
     {},
   );
 
-  return bcrypto
-    .sha256(Buffer.from(JSON.stringify(sortedContract)))
-    .slice()
-    .reverse();
+  return bcrypto.sha256(Buffer.from(JSON.stringify(sortedContract)));
 }
 
 /**