feat(sdk-coin-ada): use 1 ada as min fees

Ticket: WIN-7481

Author: Ranjna-G

modules/sdk-coin-ada/src/lib/transactionBuilder.ts

@@ -26,6 +26,8 @@ const FEE_COEFFICIENTS = {
   B_COEFFICIENT: '155381',
   /** Additional safety margin for the fee */
   SAFETY_MARGIN: '440',
+  /* Min fee required for token transaction */
+  MIN_TOKEN_TRANSACTION_FEE: '1000000',
 };
 
 export abstract class TransactionBuilder extends BaseTransactionBuilder {
@@ -377,7 +379,15 @@ export abstract class TransactionBuilder extends BaseTransactionBuilder {
     );
 
     // Calculate the fee based off our dummy transaction
-    const fee = CardanoWasm.min_fee(txDraft, linearFee).checked_add(BigNum.from_str(FEE_COEFFICIENTS.SAFETY_MARGIN));
+    let fee = CardanoWasm.min_fee(txDraft, linearFee).checked_add(BigNum.from_str(FEE_COEFFICIENTS.SAFETY_MARGIN));
+    /**
+     * In some cases especially with token transactions the calculated fee can be very low than the fee expected from the node
+     * So, ensure a minimum fee is always set
+     */
+    const minTokenFee = BigNum.from_str(FEE_COEFFICIENTS.MIN_TOKEN_TRANSACTION_FEE);
+    if (fee.less_than(minTokenFee)) {
+      fee = minTokenFee;
+    }
     this._fee = fee;
   }
 

modules/sdk-coin-ada/test/unit/tokenWithdrawal.ts

@@ -39,7 +39,7 @@ describe('ADA Token Operations', async () => {
       totalInput -
       1500000 /* min ada for change token utxo */ -
       1500000 /* min ada for recipient token utxo*/ -
-      173597
+      1000000
     ) /* fee */
       .toString();
     const expectedChangeToken = '80';
@@ -127,7 +127,7 @@ describe('ADA Token Operations', async () => {
       1500000 /* min ada for change token utxo */ -
       1500000 /* min ada for recipient token utxo*/ -
       1500000 /* min ada for unsupported token change utxo */ -
-      179889
+      1000000
     ) /* fee */
       .toString();
     const expectedChangeToken = '80';