diff --git a/src/expr/macro/src/gen.rs b/src/expr/macro/src/gen.rs
index add26829b71e3..257da1ed62ee0 100644
--- a/src/expr/macro/src/gen.rs
+++ b/src/expr/macro/src/gen.rs
@@ -219,7 +219,7 @@ impl FunctionAttr {
         };
 
         // evaluate child expressions and
-        // - build a chunk if arguments are varibale
+        // - build a chunk if arguments are variable
         // - downcast arrays if arguments are fixed
         let eval_children = if varargs {
             quote! {
@@ -238,7 +238,7 @@ impl FunctionAttr {
             }
         };
         // evaluate child expressions and
-        // - build a row if arguments are varibale
+        // - build a row if arguments are variable
         // - downcast scalars if arguments are fixed
         let eval_row_children = if varargs {
             quote! {
diff --git a/src/expr/src/sig/func.rs b/src/expr/src/sig/func.rs
index e18301f5bc942..1dcc0708ab8c5 100644
--- a/src/expr/src/sig/func.rs
+++ b/src/expr/src/sig/func.rs
@@ -128,11 +128,10 @@ mod tests {
         // convert FUNC_SIG_MAP to a more convenient map for testing
         let mut new_map: BTreeMap<PbType, BTreeMap<Vec<DataTypeName>, Vec<FuncSign>>> =
             BTreeMap::new();
-        for ((func, num_args), sigs) in &FUNC_SIG_MAP.0 {
+        for (func, sigs) in &FUNC_SIG_MAP.0 {
             for sig in sigs {
                 // validate the FUNC_SIG_MAP is consistent
                 assert_eq!(func, &sig.func);
-                assert_eq!(num_args, &sig.inputs_type.len());
                 // exclude deprecated functions
                 if sig.deprecated {
                     continue;
diff --git a/src/expr/src/vector_op/concat_ws.rs b/src/expr/src/vector_op/concat_ws.rs
index 4528ca29d672a..5fa6a542a7c74 100644
--- a/src/expr/src/vector_op/concat_ws.rs
+++ b/src/expr/src/vector_op/concat_ws.rs
@@ -45,6 +45,7 @@ mod tests {
     use risingwave_common::row::Row;
     use risingwave_common::test_prelude::DataChunkTestExt;
     use risingwave_common::types::ToOwnedDatum;
+    use risingwave_common::util::iter_util::ZipEqDebug;
 
     use crate::expr::build_from_pretty;
 
@@ -67,7 +68,7 @@ mod tests {
         assert_eq!(&output, expected.column_at(0));
 
         // test eval_row
-        for (row, expected) in input.rows().zip(expected.rows()) {
+        for (row, expected) in input.rows().zip_eq_debug(expected.rows()) {
             let result = concat_ws.eval_row(&row.to_owned_row()).await.unwrap();
             assert_eq!(result, expected.datum_at(0).to_owned_datum());
         }
diff --git a/src/expr/src/vector_op/format.rs b/src/expr/src/vector_op/format.rs
index 31d746bdeb213..a107a29a6c456 100644
--- a/src/expr/src/vector_op/format.rs
+++ b/src/expr/src/vector_op/format.rs
@@ -168,6 +168,7 @@ mod tests {
     use risingwave_common::row::Row;
     use risingwave_common::test_prelude::DataChunkTestExt;
     use risingwave_common::types::ToOwnedDatum;
+    use risingwave_common::util::iter_util::ZipEqDebug;
 
     use crate::expr::build_from_pretty;
 
@@ -178,7 +179,7 @@ mod tests {
             "T          T       T       T
              Hello%s    World   .       HelloWorld
              %s%s       Hello   World   HelloWorld
-             %I         &&              \"%%\"
+             %I         &&      .       \"&&\"
              .          a       b       .",
         )
         .split_column_at(3);
@@ -188,7 +189,7 @@ mod tests {
         assert_eq!(&output, expected.column_at(0));
 
         // test eval_row
-        for (row, expected) in input.rows().zip(expected.rows()) {
+        for (row, expected) in input.rows().zip_eq_debug(expected.rows()) {
             let result = format.eval_row(&row.to_owned_row()).await.unwrap();
             assert_eq!(result, expected.datum_at(0).to_owned_datum());
         }
diff --git a/src/frontend/src/expr/type_inference/func.rs b/src/frontend/src/expr/type_inference/func.rs
index 64e7dda9c4c96..27afd5db420fa 100644
--- a/src/frontend/src/expr/type_inference/func.rs
+++ b/src/frontend/src/expr/type_inference/func.rs
@@ -1183,6 +1183,7 @@ mod tests {
                 sig_map.insert(FuncSign {
                     func: DUMMY_FUNC,
                     inputs_type: formals,
+                    varargs: false,
                     ret_type: DUMMY_RET,
                     build: |_, _| unreachable!(),
                     deprecated: false,