From beea682c28cea561e6e0f2283d36eb12b1f6c25c Mon Sep 17 00:00:00 2001
From: Logan Nguyen <logan.nguyen@swirldslabs.com>
Date: Mon, 13 May 2024 22:13:02 -0400
Subject: [PATCH] test: added UT

Signed-off-by: Logan Nguyen <logan.nguyen@swirldslabs.com>
---
 packages/relay/src/formatters.ts            | 2 +-
 packages/relay/tests/lib/formatters.spec.ts | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/relay/src/formatters.ts b/packages/relay/src/formatters.ts
index 6161ae00b3..de5df597c4 100644
--- a/packages/relay/src/formatters.ts
+++ b/packages/relay/src/formatters.ts
@@ -147,7 +147,7 @@ const formatContractResult = (cr: any) => {
   const commonFields = {
     blockHash: toHash32(cr.block_hash),
     blockNumber: nullableNumberTo0x(cr.block_number),
-    chainId: cr.chain_id === '0x' ? undefined : cr.chain_id,
+    chainId: cr.chain_id === EMPTY_HEX ? undefined : cr.chain_id,
     from: cr.from.substring(0, 42),
     gas: nanOrNumberTo0x(cr.gas_used),
     gasPrice: toNullIfEmptyHex(cr.gas_price),
diff --git a/packages/relay/tests/lib/formatters.spec.ts b/packages/relay/tests/lib/formatters.spec.ts
index 78b190bf02..ef61d5c63a 100644
--- a/packages/relay/tests/lib/formatters.spec.ts
+++ b/packages/relay/tests/lib/formatters.spec.ts
@@ -252,6 +252,11 @@ describe('Formatters', () => {
       expect(formattedResult.yParity).to.equal('0x0');
       expect(formattedResult.value).to.equal('0x0');
     });
+
+    it('Should not include chainId field for legacy EIP155 transaction (tx.chainId=0x0)', () => {
+      const formattedResult: any = formatContractResult({ ...contractResult, chain_id: '0x' });
+      expect(formattedResult.chainId).to.be.undefined;
+    });
   });
 
   describe('prepend0x', () => {