mul_fixed_*::tests: Constrain zero outputs in mul_fixed tests.

Co-authored-by: Jack Grigg <jack@electriccoin.co>

src/circuit/gadget/ecc.rs

@@ -544,6 +544,7 @@ mod tests {
                 super::chip::mul_fixed::full_width::tests::test_mul_fixed(
                     chip.clone(),
                     layouter.namespace(|| "full-width fixed-base scalar mul"),
+                    &zero,
                 )?;
             }
 
@@ -552,6 +553,7 @@ mod tests {
                 super::chip::mul_fixed::short::tests::test_mul_fixed_short(
                     chip.clone(),
                     layouter.namespace(|| "signed short fixed-base scalar mul"),
+                    &zero,
                 )?;
             }
 
@@ -560,6 +562,7 @@ mod tests {
                 super::chip::mul_fixed::base_field_elem::tests::test_mul_fixed_base_field(
                     chip,
                     layouter.namespace(|| "fixed-base scalar mul with base field element"),
+                    &zero,
                 )?;
             }
 

src/circuit/gadget/ecc/chip/mul_fixed/base_field_elem.rs

@@ -248,7 +248,7 @@ pub mod tests {
     use crate::circuit::gadget::{
         ecc::{
             chip::{EccChip, OrchardFixedBasesFull},
-            FixedPoint,
+            FixedPoint, Point,
         },
         utilities::{CellValue, UtilitiesInstructions},
     };
@@ -257,6 +257,7 @@ pub mod tests {
     pub fn test_mul_fixed_base_field(
         chip: EccChip,
         mut layouter: impl Layouter<pallas::Base>,
+        zero: &Point<pallas::Affine, EccChip>,
     ) -> Result<(), Error> {
         impl UtilitiesInstructions<pallas::Base> for EccChip {
             type Var = CellValue<pallas::Base>;
@@ -269,6 +270,7 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "commit_ivk_r"),
             commit_ivk_r,
+            &zero,
         )?;
 
         // note_commit_r
@@ -278,6 +280,7 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "note_commit_r"),
             note_commit_r,
+            &zero,
         )?;
 
         // nullifier_k
@@ -287,6 +290,7 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "nullifier_k"),
             nullifier_k,
+            &zero,
         )?;
 
         // value_commit_r
@@ -296,12 +300,18 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "value_commit_r"),
             value_commit_r,
+            &zero,
         )?;
 
         // spend_auth_g
         let spend_auth_g = OrchardFixedBasesFull::SpendAuthG;
         let spend_auth_g = FixedPoint::from_inner(chip.clone(), spend_auth_g);
-        test_single_base(chip, layouter.namespace(|| "spend_auth_g"), spend_auth_g)?;
+        test_single_base(
+            chip,
+            layouter.namespace(|| "spend_auth_g"),
+            spend_auth_g,
+            &zero,
+        )?;
 
         Ok(())
     }
@@ -311,6 +321,7 @@ pub mod tests {
         chip: EccChip,
         mut layouter: impl Layouter<pallas::Base>,
         base: FixedPoint<pallas::Affine, EccChip>,
+        zero: &Point<pallas::Affine, EccChip>,
     ) -> Result<(), Error> {
         let column = chip.config().advices[0];
 
@@ -356,7 +367,9 @@ pub mod tests {
                 column,
                 Some(scalar_fixed),
             )?;
-            base.mul_base_field_elem(layouter.namespace(|| "mul by zero"), scalar_fixed)?;
+            let result =
+                base.mul_base_field_elem(layouter.namespace(|| "mul by zero"), scalar_fixed)?;
+            result.constrain_equal(layouter.namespace(|| "[0]B = 𝒪"), &zero)?;
         }
 
         // [-1]B is the largest base field element

src/circuit/gadget/ecc/chip/mul_fixed/full_width.rs

@@ -62,13 +62,14 @@ pub mod tests {
 
     use crate::circuit::gadget::ecc::{
         chip::{EccChip, OrchardFixedBasesFull},
-        FixedPoint, ScalarFixed,
+        FixedPoint, Point, ScalarFixed,
     };
     use crate::constants;
 
     pub fn test_mul_fixed(
         chip: EccChip,
         mut layouter: impl Layouter<pallas::Base>,
+        zero: &Point<pallas::Affine, EccChip>,
     ) -> Result<(), Error> {
         // commit_ivk_r
         let commit_ivk_r = OrchardFixedBasesFull::CommitIvkR;
@@ -77,6 +78,7 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "commit_ivk_r"),
             commit_ivk_r,
+            &zero,
         )?;
 
         // note_commit_r
@@ -86,6 +88,7 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "note_commit_r"),
             note_commit_r,
+            &zero,
         )?;
 
         // nullifier_k
@@ -95,6 +98,7 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "nullifier_k"),
             nullifier_k,
+            &zero,
         )?;
 
         // value_commit_r
@@ -104,12 +108,18 @@ pub mod tests {
             chip.clone(),
             layouter.namespace(|| "value_commit_r"),
             value_commit_r,
+            &zero,
         )?;
 
         // spend_auth_g
         let spend_auth_g = OrchardFixedBasesFull::SpendAuthG;
         let spend_auth_g = FixedPoint::from_inner(chip.clone(), spend_auth_g);
-        test_single_base(chip, layouter.namespace(|| "spend_auth_g"), spend_auth_g)?;
+        test_single_base(
+            chip,
+            layouter.namespace(|| "spend_auth_g"),
+            spend_auth_g,
+            &zero,
+        )?;
 
         Ok(())
     }
@@ -119,6 +129,7 @@ pub mod tests {
         chip: EccChip,
         mut layouter: impl Layouter<pallas::Base>,
         base: FixedPoint<pallas::Affine, EccChip>,
+        zero: &Point<pallas::Affine, EccChip>,
     ) -> Result<(), Error>
     where
         pallas::Scalar: PrimeFieldBits,
@@ -166,7 +177,8 @@ pub mod tests {
                 layouter.namespace(|| "ScalarFixed"),
                 Some(scalar_fixed),
             )?;
-            base.mul(layouter.namespace(|| "mul by zero"), &scalar_fixed)?;
+            let result = base.mul(layouter.namespace(|| "mul by zero"), &scalar_fixed)?;
+            result.constrain_equal(layouter.namespace(|| "[0]B = 𝒪"), &zero)?;
         }
 
         // [-1]B is the largest scalar field element.

src/circuit/gadget/ecc/chip/mul_fixed/short.rs

@@ -157,13 +157,14 @@ pub mod tests {
     use halo2::{circuit::Layouter, plonk::Error};
     use pasta_curves::{arithmetic::FieldExt, pallas};
 
-    use crate::circuit::gadget::ecc::{chip::EccChip, FixedPointShort, ScalarFixedShort};
+    use crate::circuit::gadget::ecc::{chip::EccChip, FixedPointShort, Point, ScalarFixedShort};
     use crate::constants::load::ValueCommitV;
 
     #[allow(clippy::op_ref)]
     pub fn test_mul_fixed_short(
         chip: EccChip,
         mut layouter: impl Layouter<pallas::Base>,
+        zero: &Point<pallas::Affine, EccChip>,
     ) -> Result<(), Error>
     where
         pallas::Scalar: PrimeFieldBits,
@@ -181,7 +182,8 @@ pub mod tests {
                 layouter.namespace(|| "ScalarFixedShort"),
                 Some(scalar_fixed),
             )?;
-            value_commit_v.mul(layouter.namespace(|| "mul"), &scalar_fixed)?;
+            let result = value_commit_v.mul(layouter.namespace(|| "mul by zero"), &scalar_fixed)?;
+            result.constrain_equal(layouter.namespace(|| "[0]B = 𝒪"), &zero)?;
         }
 
         // Random [a]B