fix(sdk-coin-etc): fix hex validation in queryAddressBalance and getAddressNonce

modules/sdk-coin-etc/src/etc.ts

@@ -296,11 +296,11 @@ export class Etc extends AbstractEthLikeCoin {
       params: [address, 'latest'],
       id: 1,
     });
-    if (!result || isNaN(result.result)) {
+    if (!result || !result.result || typeof result.result !== 'string' || !/^0x[0-9a-fA-F]*$/.test(result.result)) {
       throw new Error('Unable to find next nonce from etc.network, got: ' + JSON.stringify(result));
     }
     const nonceHex = result.result;
-    return new optionalDeps.ethUtil.BN(nonceHex.slice(2), 16).toNumber();
+    return new optionalDeps.ethUtil.BN(nonceHex.slice(2) || '0', 16).toNumber();
   }
 
   /**
@@ -322,13 +322,13 @@ export class Etc extends AbstractEthLikeCoin {
     } else if (result.error) {
       // throw if result.error exists
       throw new Error(`Could not obtain address balance for ${address} from etc.network, got: ${result.error}`);
-    } else if (!result.result || isNaN(result.result)) {
-      // throw if the result.result is not a number
+    } else if (!result.result || typeof result.result !== 'string' || !/^0x[0-9a-fA-F]*$/.test(result.result)) {
       throw new Error(`Could not obtain address balance for ${address} from etc.network, got: Incorrect Balance Hex`);
     }
 
     const nativeBalanceHex = result.result;
-    return new optionalDeps.ethUtil.BN(nativeBalanceHex.slice(2), 16);
+    // slice(2) strips '0x'; fall back to '0' if bare '0x' is returned for zero balance
+    return new optionalDeps.ethUtil.BN(nativeBalanceHex.slice(2) || '0', 16);
   }
   /**
    * Queries the contract (via explorer API) for the next sequence ID

modules/sdk-coin-etc/test/unit/etc.ts

@@ -9,6 +9,61 @@ import { getBuilder } from './getBuilder';
 import { FullySignedTransaction } from '@bitgo/sdk-core';
 import * as should from 'should';
 
+describe('queryAddressBalance', function () {
+  let bitgo: TestBitGoAPI;
+  let etcCoin: Etc;
+  let sandbox: sinon.SinonSandbox;
+
+  before(function () {
+    bitgo = TestBitGo.decorate(BitGoAPI, { env: 'mock' });
+    bitgo.initializeTestVars();
+    bitgo.safeRegister('etc', Etc.createInstance);
+    bitgo.safeRegister('tetc', Tetc.createInstance);
+  });
+
+  beforeEach(function () {
+    sandbox = sinon.createSandbox();
+    etcCoin = bitgo.coin('etc') as Etc;
+  });
+
+  afterEach(function () {
+    sandbox.restore();
+  });
+
+  it('should return the correct balance for a standard hex response', async function () {
+    sandbox.stub(etcCoin, 'recoveryBlockchainExplorerQuery').resolves({ result: '0x1bc16d674ec80000' });
+    const balance = await etcCoin.queryAddressBalance('0x1234');
+    balance.toString().should.equal('2000000000000000000');
+  });
+
+  it('should return zero for a "0x0" response', async function () {
+    sandbox.stub(etcCoin, 'recoveryBlockchainExplorerQuery').resolves({ result: '0x0' });
+    const balance = await etcCoin.queryAddressBalance('0x1234');
+    balance.toString().should.equal('0');
+  });
+
+  it('should return zero for a bare "0x" response (zero balance edge case)', async function () {
+    sandbox.stub(etcCoin, 'recoveryBlockchainExplorerQuery').resolves({ result: '0x' });
+    const balance = await etcCoin.queryAddressBalance('0x1234');
+    balance.toString().should.equal('0');
+  });
+
+  it('should throw for a missing result', async function () {
+    sandbox.stub(etcCoin, 'recoveryBlockchainExplorerQuery').resolves(null);
+    await etcCoin.queryAddressBalance('0x1234').should.be.rejectedWith(/Empty object response/);
+  });
+
+  it('should throw for an error result', async function () {
+    sandbox.stub(etcCoin, 'recoveryBlockchainExplorerQuery').resolves({ error: 'node error' });
+    await etcCoin.queryAddressBalance('0x1234').should.be.rejectedWith(/node error/);
+  });
+
+  it('should throw for a non-hex result', async function () {
+    sandbox.stub(etcCoin, 'recoveryBlockchainExplorerQuery').resolves({ result: 'not-a-hex' });
+    await etcCoin.queryAddressBalance('0x1234').should.be.rejectedWith(/Incorrect Balance Hex/);
+  });
+});
+
 describe('Ethereum Classic', function () {
   let bitgo: TestBitGoAPI;