diff --git a/__tests__/utils/ethSigner.test.ts b/__tests__/utils/ethSigner.test.ts
index 30c62903d..21b420bcc 100644
--- a/__tests__/utils/ethSigner.test.ts
+++ b/__tests__/utils/ethSigner.test.ts
@@ -159,7 +159,12 @@ describe('Ethereum signer', () => {
         { maxFee: 1 * 10 ** 16 }
       );
       const txR = await provider.waitForTransaction(respTransfer.transaction_hash);
-      expect(txR.execution_status).toBe('SUCCEEDED');
+
+      if (txR.isSuccess()) {
+        expect(txR.execution_status).toBe('SUCCEEDED');
+      } else {
+        fail('txR not success');
+      }
     });
 
     test('ETH account declaration V2', async () => {
@@ -279,7 +284,11 @@ describe('Ethereum signer', () => {
       });
 
       const txR = await provider.waitForTransaction(respTransfer.transaction_hash);
-      expect(txR.execution_status).toBe('SUCCEEDED');
+      if (txR.isSuccess()) {
+        expect(txR.execution_status).toBe('SUCCEEDED');
+      } else {
+        fail('txR not success');
+      }
     });
 
     test('ETH account declaration V3', async () => {
diff --git a/src/provider/errors.ts b/src/provider/errors.ts
index 2824dec64..1e2a01b4b 100644
--- a/src/provider/errors.ts
+++ b/src/provider/errors.ts
@@ -37,13 +37,19 @@ export class CustomError extends Error {
 export class LibraryError extends CustomError {}
 
 export class GatewayError extends LibraryError {
-  constructor(message: string, public errorCode: string) {
+  constructor(
+    message: string,
+    public errorCode: string
+  ) {
     super(message);
   }
 }
 
 export class HttpError extends LibraryError {
-  constructor(message: string, public errorCode: number) {
+  constructor(
+    message: string,
+    public errorCode: number
+  ) {
     super(message);
   }
 }
diff --git a/src/utils/transactionReceipt.ts b/src/utils/transactionReceipt.ts
index ffc353985..9cbf09909 100644
--- a/src/utils/transactionReceipt.ts
+++ b/src/utils/transactionReceipt.ts
@@ -67,15 +67,15 @@ export class ReceiptTx implements TransactionReceiptUtilityInterface {
     return (callbacks as TransactionReceiptCallbacksDefault)._();
   }
 
-  isSuccess() {
+  isSuccess(): this is SuccessfulTransactionReceiptResponse {
     return this.statusReceipt === 'success';
   }
 
-  isReverted() {
+  isReverted(): this is RevertedTransactionReceiptResponse {
     return this.statusReceipt === 'reverted';
   }
 
-  isRejected() {
+  isRejected(): this is RejectedTransactionReceiptResponse {
     return this.statusReceipt === 'rejected';
   }