diff --git a/eth/tracers/.gitignore b/eth/tracers/.gitignore
new file mode 100644
index 0000000000..203300891e
--- /dev/null
+++ b/eth/tracers/.gitignore
@@ -0,0 +1 @@
+data.csv
diff --git a/eth/tracers/api_test.go b/eth/tracers/api_test.go
index 6390a014da..5ff39130d3 100644
--- a/eth/tracers/api_test.go
+++ b/eth/tracers/api_test.go
@@ -729,7 +729,7 @@ func TestIOdump(t *testing.T) {
 				IOFlag: ioflag,
 			},
 			blockNumber: rpc.BlockNumber(genBlocks),
-			want:        `[{"result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}}]`,
+			want:        `[{"result":{"gas":21000,"failed":false,"returnValue":"0x","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"0x","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"0x","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"0x","structLogs":[]}},{"result":{"gas":21000,"failed":false,"returnValue":"0x","structLogs":[]}}]`,
 		},
 	}