fix: Mock Challenges with different values (scroll-tech#930)

* fix: Mock `Challenges` with different values

As mentioned in scroll-tech#926, the `Challenges::mock` function was not adding
different values for the `Challenges`. Therefore, a new function has
been added that allows mocking by passing two different values (one per
each challenge).

This allows to keep the API we previously had and also, reduce the need
to send always 2 values when only 1 can be passed.

Resolves: scroll-tech#926

* fix: Apply @han0110's suggestions

zkevm-circuits/src/copy_circuit.rs

@@ -658,7 +658,8 @@ pub mod dev {
         ) -> Result<(), halo2_proofs::plonk::Error> {
             let block = self.block.as_ref().unwrap();
 
-            let challenges = Challenges::mock(Value::known(self.randomness));
+            let challenges =
+                Challenges::mock(Value::known(self.randomness), Value::known(self.randomness));
 
             config
                 .tx_table

zkevm-circuits/src/evm_circuit.rs

@@ -288,7 +288,10 @@ pub mod test {
             mut layouter: impl Layouter<F>,
         ) -> Result<(), Error> {
             let block = self.block.as_ref().unwrap();
-            let challenges = Challenges::mock(Value::known(block.randomness));
+            let challenges = Challenges::mock(
+                Value::known(block.randomness),
+                Value::known(block.randomness),
+            );
 
             config
                 .evm_circuit

zkevm-circuits/src/super_circuit.rs

@@ -183,7 +183,10 @@ impl<F: Field, const MAX_TXS: usize, const MAX_CALLDATA: usize, const MAX_RWS: u
             Expression::Constant(F::from(MOCK_RANDOMNESS).pow(&[1 + i as u64, 0, 0, 0]))
         });
 
-        let challenges = Challenges::mock(power_of_randomness[0].clone());
+        let challenges = Challenges::mock(
+            power_of_randomness[0].clone(),
+            power_of_randomness[0].clone(),
+        );
 
         let keccak_circuit = KeccakConfig::configure(meta, power_of_randomness[0].clone());
         let keccak_table = keccak_circuit.keccak_table.clone();
@@ -246,7 +249,10 @@ impl<F: Field, const MAX_TXS: usize, const MAX_CALLDATA: usize, const MAX_RWS: u
         mut layouter: impl Layouter<F>,
     ) -> Result<(), Error> {
         let block = self.block.as_ref().unwrap();
-        let challenges = Challenges::mock(Value::known(block.randomness));
+        let challenges = Challenges::mock(
+            Value::known(block.randomness),
+            Value::known(block.randomness),
+        );
 
         // --- EVM Circuit ---
         let rws = block.rws.table_assignments();

zkevm-circuits/src/util.rs

@@ -91,10 +91,10 @@ impl<T: Clone> Challenges<T> {
         self.keccak_input.clone()
     }
 
-    pub(crate) fn mock(challenge: T) -> Self {
+    pub(crate) fn mock(evm_word: T, keccak_input: T) -> Self {
         Self {
-            evm_word: challenge.clone(),
-            keccak_input: challenge,
+            evm_word,
+            keccak_input,
         }
     }
 }