Merge pull request #273 from Leothosine/feat/issue-172-fee-generator

feat(devkit): add synthetic fee sequence generator

Author: Tinna23

packages/devkit/src/lib.rs

@@ -1,6 +1,7 @@
-pub mod analysis;
+pub mod analysis;
 pub mod cli;
 pub mod error;
 pub mod harness;
 pub mod simulation;
-pub mod types;
+pub mod test_helpers;
+pub mod types;

packages/devkit/src/test_helpers/mod.rs

@@ -0,0 +1,50 @@
+//! Test helpers: deterministic fee sequence generator and SQLite fixture builder.
+
+use rand::{Rng, SeedableRng};
+use rand::rngs::SmallRng;
+
+/// Generates a deterministic fee sequence from a seed for repeatable tests.
+pub struct FeeGenerator {
+    rng: SmallRng,
+}
+
+impl FeeGenerator {
+    /// Create a generator with the given seed.
+    pub fn new(seed: u64) -> Self {
+        Self { rng: SmallRng::seed_from_u64(seed) }
+    }
+
+    /// Generate `n` fee values in the range [min_fee, max_fee].
+    pub fn generate(&mut self, n: usize, min_fee: u64, max_fee: u64) -> Vec<u64> {
+        (0..n).map(|_| self.rng.gen_range(min_fee..=max_fee)).collect()
+    }
+
+    /// Generate a flat sequence of `n` identical fees (useful for baseline tests).
+    pub fn flat(fee: u64, n: usize) -> Vec<u64> {
+        vec![fee; n]
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn same_seed_produces_same_sequence() {
+        let a = FeeGenerator::new(42).generate(10, 100, 1000);
+        let b = FeeGenerator::new(42).generate(10, 100, 1000);
+        assert_eq!(a, b);
+    }
+
+    #[test]
+    fn different_seeds_produce_different_sequences() {
+        let a = FeeGenerator::new(1).generate(10, 100, 1000);
+        let b = FeeGenerator::new(2).generate(10, 100, 1000);
+        assert_ne!(a, b);
+    }
+
+    #[test]
+    fn flat_returns_uniform_sequence() {
+        assert_eq!(FeeGenerator::flat(500, 5), vec![500u64; 5]);
+    }
+}