From 69e06063032f72f49c3d8b1dc06c9acd67e250d0 Mon Sep 17 00:00:00 2001
From: Alla Gopi Karath <gopikarath@bitgo.com>
Date: Tue, 18 Nov 2025 15:45:29 +0530
Subject: [PATCH] feat(sdk-coin-dot): add verify transaction function

WIN-7596

TICKET: WIN-7596
---
 modules/sdk-coin-dot/src/dot.ts       | 35 +++++++++++++++-
 modules/sdk-coin-dot/test/unit/dot.ts | 59 ++++++++++++++++++++++++++-
 2 files changed, 92 insertions(+), 2 deletions(-)

diff --git a/modules/sdk-coin-dot/src/dot.ts b/modules/sdk-coin-dot/src/dot.ts
index 3066f3fa26..3112215fde 100644
--- a/modules/sdk-coin-dot/src/dot.ts
+++ b/modules/sdk-coin-dot/src/dot.ts
@@ -651,12 +651,45 @@ export class Dot extends BaseCoin {
   }
 
   async verifyTransaction(params: VerifyTransactionOptions): Promise<boolean> {
-    const { txParams } = params;
+    const { txPrebuild, txParams } = params;
+    if (!txParams) {
+      throw new Error('missing txParams');
+    }
+
+    if (!txPrebuild) {
+      throw new Error('missing txPrebuild');
+    }
+
+    if (!txPrebuild.txHex) {
+      throw new Error('missing txHex in txPrebuild');
+    }
+
+    if (!txParams.recipients || txParams.recipients.length === 0) {
+      throw new Error('missing recipients in txParams');
+    }
+
+    const factory = this.getBuilder();
+    const txBuilder = factory.from(txPrebuild.txHex) as any;
+
     if (Array.isArray(txParams.recipients) && txParams.recipients.length > 1) {
       throw new Error(
         `${this.getChain()} doesn't support sending to more than 1 destination address within a single transaction. Try again, using only a single recipient.`
       );
     }
+
+    // validate recipient is same as txBuilder._to
+    if (txParams.recipients[0].address !== txBuilder._to) {
+      throw new Error(
+        `Recipient address ${txParams.recipients[0].address} does not match transaction destination address ${txBuilder._to}`
+      );
+    }
+
+    // and amount is same as txBuilder._amount
+    if (txParams.recipients[0].amount !== txBuilder._amount) {
+      throw new Error(
+        `Recipient amount ${txParams.recipients[0].amount} does not match transaction amount ${txBuilder._amount}`
+      );
+    }
     return true;
   }
 
diff --git a/modules/sdk-coin-dot/test/unit/dot.ts b/modules/sdk-coin-dot/test/unit/dot.ts
index 21a618e538..dbbbad51fc 100644
--- a/modules/sdk-coin-dot/test/unit/dot.ts
+++ b/modules/sdk-coin-dot/test/unit/dot.ts
@@ -664,12 +664,69 @@ describe('DOT:', function () {
         walletPassphrase: 'fakeWalletPassphrase',
       };
 
+      const txPrebuild = {
+        txHex:
+          '0xa80a0300161b969b6b53ef81225feea3882284c778cd4a406d23215fcf492e83f75d42960b00204aa9d101eb600400000065900f001000000067f9723393ef76214df0118c34bbbd3dbebc8ed46a10973a8c969d48fe7598c9a7b7420ee3e4fe2b88da0fc42b30897e18d56d8b56a1934211d9de730cf96de300',
+      };
+
       await basecoin
-        .verifyTransaction({ txParams })
+        .verifyTransaction({ txPrebuild, txParams })
         .should.be.rejectedWith(
           `tdot doesn't support sending to more than 1 destination address within a single transaction. Try again, using only a single recipient.`
         );
     });
+
+    it('should reject a txPrebuild with more than invalid amount', async function () {
+      const wallet = new Wallet(bitgo, basecoin, {});
+      const txParams = {
+        recipients: [{ amount: '20000000000', address: '5CZh773vKGwKFCYUjGc31AwXCbf7TPkavdeuk2XoujJMjbBD' }],
+        wallet: wallet,
+        walletPassphrase: 'fakeWalletPassphrase',
+      };
+      const txPrebuild = {
+        txHex:
+          '0xa80a0300161b969b6b53ef81225feea3882284c778cd4a406d23215fcf492e83f75d42960b00204aa9d101eb600400000065900f001000000067f9723393ef76214df0118c34bbbd3dbebc8ed46a10973a8c969d48fe7598c9a7b7420ee3e4fe2b88da0fc42b30897e18d56d8b56a1934211d9de730cf96de300',
+      };
+
+      await basecoin
+        .verifyTransaction({ txPrebuild, txParams })
+        .should.be.rejectedWith(`Recipient amount 20000000000 does not match transaction amount 2000000000000`);
+    });
+
+    it('should reject a txPrebuild with more than invalid recipient', async function () {
+      const wallet = new Wallet(bitgo, basecoin, {});
+      const txParams = {
+        recipients: [{ amount: '2000000000000', address: '5CZh773vKGwKFCUjGc31AwXCbf7TPkavduk2XoujJMjbBD' }],
+        wallet: wallet,
+        walletPassphrase: 'fakeWalletPassphrase',
+      };
+      const txPrebuild = {
+        txHex:
+          '0xa80a0300161b969b6b53ef81225feea3882284c778cd4a406d23215fcf492e83f75d42960b00204aa9d101eb600400000065900f001000000067f9723393ef76214df0118c34bbbd3dbebc8ed46a10973a8c969d48fe7598c9a7b7420ee3e4fe2b88da0fc42b30897e18d56d8b56a1934211d9de730cf96de300',
+      };
+
+      await basecoin
+        .verifyTransaction({ txPrebuild, txParams })
+        .should.be.rejectedWith(
+          `Recipient address 5CZh773vKGwKFCUjGc31AwXCbf7TPkavduk2XoujJMjbBD does not match transaction destination address 5CZh773vKGwKFCYUjGc31AwXCbf7TPkavdeuk2XoujJMjbBD`
+        );
+    });
+
+    it('should accept a txPrebuild with more than valid recipient and amount', async function () {
+      const wallet = new Wallet(bitgo, basecoin, {});
+      const txParams = {
+        recipients: [{ amount: '2000000000000', address: '5CZh773vKGwKFCYUjGc31AwXCbf7TPkavdeuk2XoujJMjbBD' }],
+        wallet: wallet,
+        walletPassphrase: 'fakeWalletPassphrase',
+      };
+      const txPrebuild = {
+        txHex:
+          '0xa80a0300161b969b6b53ef81225feea3882284c778cd4a406d23215fcf492e83f75d42960b00204aa9d101eb600400000065900f001000000067f9723393ef76214df0118c34bbbd3dbebc8ed46a10973a8c969d48fe7598c9a7b7420ee3e4fe2b88da0fc42b30897e18d56d8b56a1934211d9de730cf96de300',
+      };
+
+      const result = await basecoin.verifyTransaction({ txPrebuild, txParams });
+      assert.strictEqual(result, true);
+    });
   });
 
   describe('isWalletAddress', () => {