Fuzzing test fix

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
     name: Lint (${{ matrix.os }} + ${{ matrix.channel }})
     needs: [format, format-cargo-toml, docs]
     strategy:
-      fail-fast: false
+      fail-fast: true
       matrix:
         os:
           - ubuntu-latest
@@ -58,15 +58,16 @@ jobs:
       - run: cargo hakari manage-deps --yes
       - run: cargo hakari verify
       - run: cargo install cargo-hack --locked
+      - run: cargo clippy --workspace --all-features -vv
+      - run: cargo hack clippy --workspace --feature-powerset --tests
       - run: cargo hack clippy --workspace --feature-powerset
       - run: cargo hack clippy --workspace --feature-powerset --bins
       - run: cargo hack clippy --workspace --feature-powerset --examples
-      - run: cargo hack clippy --workspace --feature-powerset --tests
   test:
     name: Test (${{ matrix.os }} + ${{ matrix.channel }})
     needs: [format, format-cargo-toml, docs]
     strategy:
-      fail-fast: false
+      fail-fast: true
       matrix:
         os:
           - macos-latest
@@ -85,7 +86,7 @@ jobs:
     name: Compile Benchmarks (${{ matrix.os }} + ${{ matrix.channel }})
     needs: [format, format-cargo-toml, docs]
     strategy:
-      fail-fast: false
+      fail-fast: true
       matrix:
         os:
           - macos-latest

CHANGELOG.md

@@ -14,6 +14,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Removed
 
 ### Fixed
+- [\#302](https://github.com/Manta-Network/manta-rs/pull/302) Fix fuzzing test bug
 - [\#296](https://github.com/Manta-Network/manta-rs/pull/296) Fix AssetMetadata display for values less than 1
 - [\#294](https://github.com/Manta-Network/manta-rs/pull/294) Distinguish between panic-errors and possible-fix-errors
 

manta-crypto/src/arkworks/ff.rs

@@ -17,6 +17,7 @@
 //! Arkworks Finite Field Backend
 
 use manta_util::{byte_count, into_array_unchecked};
+use num_integer::Integer;
 
 #[doc(inline)]
 pub use ark_ff::*;
@@ -53,6 +54,23 @@ field_try_into! {
    try_into_u128 => u128,
 }
 
+/// Divides the [`BigInteger`]s `n` by `m` and returns the quotient and the remainder.
+#[inline]
+pub fn div_rem<B>(n: B, m: B) -> (B, B)
+where
+    B: BigInteger,
+{
+    let (quotient, remainder) = n.into().div_rem(&m.into());
+    (
+        B::try_from(quotient)
+            .ok()
+            .expect("Unable to compute modular reduction."),
+        B::try_from(remainder)
+            .ok()
+            .expect("Unable to compute modular reduction."),
+    )
+}
+
 /// Testing Suite
 #[cfg(test)]
 mod test {

manta-crypto/src/rand.rs

@@ -539,7 +539,7 @@ pub mod fuzz {
     use super::*;
 
     #[cfg(all(feature = "arkworks", feature = "rand"))]
-    use crate::arkworks::ff::{BigInteger, PrimeField};
+    use crate::arkworks::ff::{div_rem, BigInteger, FpParameters, PrimeField};
 
     /// Fuzz Trait
     pub trait Fuzz<M = ()> {
@@ -612,7 +612,8 @@ pub mod fuzz {
         where
             R: RngCore + ?Sized,
         {
-            P::from_repr(self.into_repr().fuzz(rng))
+            let (_, fuzzed_element) = div_rem(self.into_repr().fuzz(rng), P::Params::MODULUS);
+            P::from_repr(fuzzed_element)
                 .expect("Computing the field element from a big integer is not supposed to fail.")
         }
     }