test: fix conversion of sum of GroupVars

Author: mmaker

src/linear_relation/convert.rs

@@ -148,14 +148,10 @@ impl<G: Group> From<ScalarTerm<G>> for Sum<Weighted<ScalarTerm<G>, G::Scalar>> {
     }
 }
 
-// Convert a Sum with a single Weighted<GroupVar, Scalar> to Weighted<Term, Scalar>
-impl<G: Group> From<Sum<Weighted<GroupVar<G>, G::Scalar>>> for Weighted<Term<G>, G::Scalar> {
+impl<G: Group> From<Sum<Weighted<GroupVar<G>, G::Scalar>>> for Sum<Weighted<Term<G>, G::Scalar>> {
     fn from(sum: Sum<Weighted<GroupVar<G>, G::Scalar>>) -> Self {
-        assert_eq!(
-            sum.0.len(),
-            1,
-            "Can only convert Sum with exactly one element to Weighted<Term>"
-        );
-        sum.0.into_iter().next().unwrap().into()
+        let sum = sum.0.into_iter().map(|x| x.into()).collect::<Vec<_>>();
+        Self(sum)
     }
-}
+
+}

src/tests/test_validation_criteria.rs

@@ -135,13 +135,16 @@ mod instance_validation {
     #[test]
     fn without_witness() {
         let B = G::generator();
-        let x = Scalar::from(42);
+        let A = G::generator() * Scalar::from(42);
+        let pub_scalar = Scalar::from(42);
 
         let mut linear_relation = LinearRelation::<G>::new();
         let B_var = linear_relation.allocate_element();
-        let _X_var = linear_relation.allocate_eq(B_var * x + B_var * Scalar::from(3));
+        let A_var = linear_relation.allocate_element();
+        let _X_var = linear_relation.allocate_eq(B_var * pub_scalar + A_var * Scalar::from(3));
 
         linear_relation.set_element(B_var, B);
+        linear_relation.set_element(A_var, A);
         let result = CanonicalLinearRelation::try_from(&linear_relation);
         assert!(result.is_err());
     }