feat(sdk-api): add test for isTestTransaction in sendMany

Add unit test to verify that isTestTransaction parameter is properly
passed through the sendMany -> prebuildAndSignTransaction flow for
TSS wallets. This ensures the parameter flows correctly via inheritance
from SendManyOptions -> PrebuildAndSignTransactionOptions ->
PrebuildTransactionOptions.

Author: sandra-wang-bitgo

modules/bitgo/test/v2/unit/wallet.ts

@@ -2386,7 +2386,8 @@ describe('V2 Wallet:', function () {
         callArgs.should.have.property('isTestTransaction', true);
         callArgs.should.have.property('intentType', 'payment');
         callArgs.should.have.property('recipients');
-        callArgs.recipients.should.deepEqual(recipients);
+        should.exist(callArgs.recipients);
+        callArgs.recipients!.should.deepEqual(recipients);
 
         txPrebuild.should.deepEqual({
           walletId: tssSolWallet.id(),
@@ -3952,6 +3953,35 @@ describe('V2 Wallet:', function () {
         setRequestTracerSpy.restore();
       });
 
+      it('should pass isTestTransaction through sendMany to prebuildAndSignTransaction', async function () {
+        const signedTransaction = {
+          txRequestId: 'txRequestId',
+        };
+
+        const sendManyInputWithTestFlag = {
+          ...sendManyInput,
+          type: 'transfer',
+          isTestTransaction: true,
+        };
+
+        const prebuildAndSignTransaction = sandbox.stub(tssSolWallet, 'prebuildAndSignTransaction');
+        prebuildAndSignTransaction.resolves(signedTransaction);
+
+        const sendTxRequest = sandbox.stub(TssUtils.prototype, 'sendTxRequest');
+        sendTxRequest.resolves('sendTxResponse');
+
+        const sendMany = await tssSolWallet.sendMany(sendManyInputWithTestFlag);
+
+        // Verify prebuildAndSignTransaction was called with isTestTransaction
+        sinon.assert.calledOnce(prebuildAndSignTransaction);
+        const callArgs = prebuildAndSignTransaction.getCall(0).args[0];
+        should.exist(callArgs);
+        callArgs!.should.have.property('isTestTransaction', true);
+        callArgs!.should.have.property('type', 'transfer');
+
+        sendMany.should.deepEqual('sendTxResponse');
+      });
+
       it('should return transfer from sendMany for apiVersion=full', async function () {
         const wallet = new Wallet(bitgo, tsol, {
           ...walletData,