From d99cabded9b8f05e46f81665b8f9dc0d844d8f7d Mon Sep 17 00:00:00 2001
From: wborgeaud <williamborgeaud@gmail.com>
Date: Fri, 4 Feb 2022 15:56:59 +0100
Subject: [PATCH] Working

---
 starky/src/fibonacci_stark.rs  | 18 ++++++++++++++++++
 starky/src/lib.rs              |  2 ++
 starky/src/stark.rs            |  3 +++
 system_zero/src/system_zero.rs |  4 ++++
 4 files changed, 27 insertions(+)

diff --git a/starky/src/fibonacci_stark.rs b/starky/src/fibonacci_stark.rs
index f3ffd8a2..ad9685bb 100644
--- a/starky/src/fibonacci_stark.rs
+++ b/starky/src/fibonacci_stark.rs
@@ -81,6 +81,10 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for FibonacciStar
     ) {
         todo!()
     }
+
+    fn degree(&self) -> usize {
+        2
+    }
 }
 
 #[cfg(test)]
@@ -93,6 +97,7 @@ mod tests {
     use crate::config::StarkConfig;
     use crate::fibonacci_stark::FibonacciStark;
     use crate::prover::prove;
+    use crate::stark_testing::test_low_degree;
     use crate::verifier::verify;
 
     fn fibonacci(n: usize, x0: usize, x1: usize) -> usize {
@@ -125,4 +130,17 @@ mod tests {
 
         verify(stark, proof, &config)
     }
+
+    #[test]
+    fn test_fibonacci_stark_degree() -> Result<()> {
+        const D: usize = 2;
+        type C = PoseidonGoldilocksConfig;
+        type F = <C as GenericConfig<D>>::F;
+        type S = FibonacciStark<F, D>;
+
+        let config = StarkConfig::standard_fast_config();
+        let num_rows = 1 << 5;
+        let stark = S::new(num_rows);
+        test_low_degree(stark)
+    }
 }
diff --git a/starky/src/lib.rs b/starky/src/lib.rs
index e56c0ef6..dd3a6ec3 100644
--- a/starky/src/lib.rs
+++ b/starky/src/lib.rs
@@ -17,3 +17,5 @@ pub mod verifier;
 
 #[cfg(test)]
 pub mod fibonacci_stark;
+#[cfg(test)]
+pub mod stark_testing;
diff --git a/starky/src/stark.rs b/starky/src/stark.rs
index 00441240..9721c203 100644
--- a/starky/src/stark.rs
+++ b/starky/src/stark.rs
@@ -62,6 +62,9 @@ pub trait Stark<F: RichField + Extendable<D>, const D: usize>: Sync {
         yield_constr: &mut RecursiveConstraintConsumer<F, D>,
     );
 
+    /// The maximum constraint degree.
+    fn degree(&self) -> usize;
+
     /// Computes the FRI instance used to prove this Stark.
     // TODO: Permutation polynomials.
     fn fri_instance(
diff --git a/system_zero/src/system_zero.rs b/system_zero/src/system_zero.rs
index 31b8434f..e5990af9 100644
--- a/system_zero/src/system_zero.rs
+++ b/system_zero/src/system_zero.rs
@@ -80,6 +80,10 @@ impl<F: RichField + Extendable<D>, const D: usize> Stark<F, D> for SystemZero<F,
         self.eval_permutation_unit_recursively(builder, vars, yield_constr);
         todo!()
     }
+
+    fn degree(&self) -> usize {
+        3
+    }
 }
 
 #[cfg(test)]