diff --git a/packages/devkit/src/lib.rs b/packages/devkit/src/lib.rs
index 41ba9eb..729e489 100644
--- a/packages/devkit/src/lib.rs
+++ b/packages/devkit/src/lib.rs
@@ -4,4 +4,4 @@ pub mod error;
 pub mod harness;
 pub mod simulation;
 pub mod test_helpers;
-pub mod types;
\ No newline at end of file
+pub mod types;
diff --git a/packages/devkit/src/test_helpers/mod.rs b/packages/devkit/src/test_helpers/mod.rs
index 08762ee..b601a87 100644
--- a/packages/devkit/src/test_helpers/mod.rs
+++ b/packages/devkit/src/test_helpers/mod.rs
@@ -1,3 +1,34 @@
+use crate::simulation::fee_model::{FeeModel, FeeModelConfig};
+use crate::types::FeeRecord;
+
+/// Returns a deterministic fee sequence of `count` records seeded by `seed`.
+pub fn make_fee_sequence(count: usize, seed: u64) -> Vec<FeeRecord> {
+    let config = FeeModelConfig {
+        seed: Some(seed),
+        ..Default::default()
+    };
+    FeeModel::new(config).generate(count, 0)
+}
+
+/// Returns a fee sequence where every record is flagged as a spike.
+pub fn make_spike_sequence(count: usize) -> Vec<FeeRecord> {
+    let config = FeeModelConfig {
+        spike_probability: 1.0,
+        seed: Some(0),
+        ..Default::default()
+    };
+    FeeModel::new(config).generate(count, 0)
+}
+
+/// Returns a fee sequence with no spikes (baseline load only).
+pub fn make_baseline_sequence(count: usize) -> Vec<FeeRecord> {
+    let config = FeeModelConfig {
+        spike_probability: 0.0,
+        seed: Some(1),
+        ..Default::default()
+    };
+    FeeModel::new(config).generate(count, 0)
+}
 //! Test helpers: deterministic fee sequence generator and SQLite fixture builder.
 
 use rand::{Rng, SeedableRng};
@@ -83,4 +114,4 @@ mod tests {
     fn flat_returns_uniform_sequence() {
         assert_eq!(FeeGenerator::flat(500, 5), vec![500u64; 5]);
     }
-}
\ No newline at end of file
+}