diff --git a/crates/coremem/src/sim/spirv/mod.rs b/crates/coremem/src/sim/spirv/mod.rs
index edeccaa..20b02df 100644
--- a/crates/coremem/src/sim/spirv/mod.rs
+++ b/crates/coremem/src/sim/spirv/mod.rs
@@ -270,9 +270,17 @@ where
 #[cfg(test)]
 mod test {
     use super::*;
+    use crate::mat::{self, AnisomorphicConductor};
+    use crate::meas::Energy;
     use crate::real::{R32, ToFloat as _};
     use crate::sim::legacy::{self, SimState};
-    use crate::mat::{self, AnisomorphicConductor};
+    use crate::stim::{
+        self,
+        ModulatedVectorField,
+        Sinusoid,
+        StimExt as _,
+        VectorField,
+    };
     fn mean_magnitude_e<S: AbstractSim>(sim: &S) -> R32 {
         let m = sim.map_sum_enumerated(|_pos: Index, cell| {
             cell.e().mag().to_r64()
@@ -336,6 +344,47 @@ mod test {
         }
     }
 
+
+    /// used in a ModulatedVectorField to apply a modulation to a *specific* index
+    struct IndexGatedEField {
+        loc: Index,
+    }
+
+    impl<R: Real> VectorField<R> for IndexGatedEField {
+        fn at(&self, _feat_size: R, loc: Index) -> stim::Fields<R> {
+            if loc == self.loc {
+                stim::Fields::new_e(Vec3::new(0.0, 0.0, 1.0).cast())
+            } else {
+                stim::Fields::default()
+            }
+        }
+    }
+
+    /// returns a Stimulus which will create a smooth pulse at t=0 through to t=<frames>,
+    ///   at only the provided location.
+    /// caller can expect that its energy content is relatively focused to just the wavelength
+    /// `frames`.
+    fn smooth_pulse_at(timestep: f32, feat_size: f32, loc: Index, frames: u32) -> impl Stimulus<R32> {
+        let wl = (timestep * frames as f32).to_r32();
+        let quarter_wl = wl * (0.25).to_r32();
+        let amp = (timestep*feat_size*feat_size).inv().to_r32();
+        let window = Sinusoid::from_wavelength(R32::one(), wl)
+            .shifted(quarter_wl)
+            .summed(R32::one());
+        ModulatedVectorField::new(
+            IndexGatedEField { loc },
+            Sinusoid::from_wavelength(amp, wl).scaled(window),
+        )
+    }
+
+    /// step by ones, applying the stimulus at each step, and return the energy at the end.
+    fn step_n<S: AbstractSim, Stim: Stimulus<S::Real>>(state: &mut S, stim: &Stim, frames: u32) -> f32 {
+        for _ in 0..frames {
+            state.step_multiple(1, stim);
+        }
+        Energy::world().data(state)
+    }
+
     mod backend_agnostic {
         use super::*;
         use crate::stim::{Fields, NoopStimulus, RngStimulus};
@@ -611,15 +660,7 @@ mod test {
                 use super::*;
 
                 use crate::geom::WorldRegion;
-                use crate::meas::Energy;
-                use crate::stim::{
-                    self,
-                    ModulatedVectorField,
-                    NoopStimulus,
-                    Sinusoid,
-                    StimExt as _,
-                    VectorField
-                };
+                use crate::stim::NoopStimulus;
                 use coremem_cross::mat::{AnisomorphicConductor, IsomorphicConductor};
                 use float_eq::assert_float_eq;
                 use more_asserts::{assert_gt, assert_lt};
@@ -638,45 +679,6 @@ mod test {
                     assert_eq!(state.time(), state.timestep());
                 }
 
-                /// used in a ModulatedVectorField to apply a modulation to a *specific* index
-                struct IndexGatedEField {
-                    loc: Index,
-                }
-
-                impl<R: Real> VectorField<R> for IndexGatedEField {
-                    fn at(&self, _feat_size: R, loc: Index) -> stim::Fields<R> {
-                        if loc == self.loc {
-                            stim::Fields::new_e(Vec3::new(0.0, 0.0, 1.0).cast())
-                        } else {
-                            stim::Fields::default()
-                        }
-                    }
-                }
-
-                fn smooth_pulse_at(timestep: f32, feat_size: f32, loc: Index, frames: u32) -> impl Stimulus<R32> {
-                    let wl = (timestep * frames as f32).to_r32();
-                    let quarter_wl = wl * (0.25).to_r32();
-                    let amp = (timestep*feat_size*feat_size).inv().to_r32();
-                    let window = Sinusoid::from_wavelength(R32::one(), wl)
-                        .shifted(quarter_wl)
-                        .summed(R32::one());
-                    ModulatedVectorField::new(
-                        IndexGatedEField { loc },
-                        // amp,
-                        // window.scaled(amp),
-                        // Sinusoid::from_wavelength(amp, wl).shifted(quarter_wl)
-                        // Sinusoid::from_wavelength(amp, wl * R32::two()),
-                        Sinusoid::from_wavelength(amp, wl).scaled(window),
-                    )
-                }
-
-                fn step_n<S: AbstractSim, Stim: Stimulus<S::Real>>(state: &mut S, stim: &Stim, frames: u32) -> f32 {
-                    for _ in 0..frames {
-                        state.step_multiple(1, stim);
-                    }
-                    Energy::world().data(state)
-                }
-
                 #[test]
                 fn energy_conservation_over_time() {
                     let mut state = SpirvSim::<R32, FullyGenericMaterial<R32>, $backend>::new(