diff --git a/triton-constraint-circuit/src/lib.rs b/triton-constraint-circuit/src/lib.rs
index 2dafecf4..2c7afff4 100644
--- a/triton-constraint-circuit/src/lib.rs
+++ b/triton-constraint-circuit/src/lib.rs
@@ -1230,53 +1230,53 @@ mod tests {
             self_expression.contains(other_expression)
         }
 
+        /// Produces an iter over all nodes in the multicircuit, if it is non-empty.
+        ///
+        /// Helper function for counting the number of nodes of a specific type.
+        fn iter_nodes(
+            constraints: &[Self],
+        ) -> std::vec::IntoIter<(usize, ConstraintCircuitMonad<II>)> {
+            if let Some(first) = constraints.first() {
+                first
+                    .builder
+                    .all_nodes
+                    .borrow()
+                    .iter()
+                    .map(|(n, m)| (*n, m.clone()))
+                    .collect_vec()
+                    .into_iter()
+            } else {
+                vec![].into_iter()
+            }
+        }
+
         /// Counts the number of inputs from the main table
         fn num_nodes(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .len()
+            Self::iter_nodes(constraints).count()
+        }
+
+        /// Determine if the constraint circuit monad corresponds to a main table
+        /// column.
+        fn is_main_table_column(&self) -> bool {
+            if let CircuitExpression::Input(ii) = self.circuit.as_ref().borrow().expression {
+                ii.is_main_table_column()
+            } else {
+                false
+            }
         }
 
         /// Counts the number of inputs from the main table
         fn num_main_inputs(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .iter()
-                .filter(|(_, cc)| {
-                    if let CircuitExpression::Input(ii) = cc.circuit.as_ref().borrow().expression {
-                        ii.is_main_table_column()
-                    } else {
-                        false
-                    }
-                })
+            Self::iter_nodes(constraints)
+                .filter(|(_, cc)| cc.is_main_table_column())
                 .filter(|(_, cc)| cc.circuit.borrow().evaluates_to_base_element())
                 .count()
         }
 
         /// Counts the number of inputs from the aux table
         fn num_aux_inputs(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .iter()
-                .filter(|(_, cc)| {
-                    if let CircuitExpression::Input(ii) = cc.circuit.as_ref().borrow().expression {
-                        !ii.is_main_table_column()
-                    } else {
-                        false
-                    }
-                })
+            Self::iter_nodes(constraints)
+                .filter(|(_, cc)| !cc.is_main_table_column())
                 .count()
         }
 
@@ -1287,13 +1287,7 @@ mod tests {
 
         /// Counts the number of challenges
         fn num_challenges(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .iter()
+            Self::iter_nodes(constraints)
                 .filter(|(_, cc)| {
                     matches!(
                         cc.circuit.as_ref().borrow().expression,
@@ -1305,13 +1299,7 @@ mod tests {
 
         /// Counts the number of `BinOp`s
         fn num_binops(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .iter()
+            Self::iter_nodes(constraints)
                 .filter(|(_, cc)| {
                     matches!(
                         cc.circuit.as_ref().borrow().expression,
@@ -1323,13 +1311,7 @@ mod tests {
 
         /// Counts the number of BFE constants
         fn num_bfield_constants(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .iter()
+            Self::iter_nodes(constraints)
                 .filter(|(_, cc)| {
                     matches!(
                         cc.circuit.as_ref().borrow().expression,
@@ -1341,13 +1323,7 @@ mod tests {
 
         /// Counts the number of XFE constants
         fn num_xfield_constants(constraints: &[Self]) -> usize {
-            constraints
-                .first()
-                .unwrap()
-                .builder
-                .all_nodes
-                .borrow()
-                .iter()
+            Self::iter_nodes(constraints)
                 .filter(|(_, cc)| {
                     matches!(
                         cc.circuit.as_ref().borrow().expression,