refactor invoice required confirmations resolver to be more scalable for future confirmations based coins

backend/src/utils/invoice/resolveInvoiceRequiredConfirmations.spec.ts

@@ -17,14 +17,32 @@ describe('resolveInvoiceRequiredConfirmations', () => {
                 paymentMethod: PaymentMethod.Xmr,
                 moneroDetails: null
             })
-        ).toThrow('Invoice is missing Monero required confirmations');
+        ).toThrow('Invoice is missing xmr required confirmations');
+    });
+
+    it('returns required confirmations for BTC invoices', () => {
+        expect(
+            resolveInvoiceRequiredConfirmations({
+                paymentMethod: PaymentMethod.Btc,
+                btcDetails: { requiredConfirmations: 6 }
+            })
+        ).toBe(6);
+    });
+
+    it('throws when bitcoin details are missing', () => {
+        expect(() =>
+            resolveInvoiceRequiredConfirmations({
+                paymentMethod: PaymentMethod.Btc,
+                btcDetails: null
+            })
+        ).toThrow('Invoice is missing btc required confirmations');
     });
 
     it('throws for unsupported payment methods', () => {
         expect(() =>
             resolveInvoiceRequiredConfirmations({
-                paymentMethod: 'btc' as PaymentMethod
+                paymentMethod: 'eth' as PaymentMethod
             })
-        ).toThrow('Unsupported payment method: btc');
+        ).toThrow('Invoice is missing eth required confirmations');
     });
 });