From 54609eab1a40d9f2d556501968a37a06020d181a Mon Sep 17 00:00:00 2001
From: Jeroen Schweitzer <jpmschweitzer@gmail.com>
Date: Mon, 8 Jun 2026 18:36:41 +0200
Subject: [PATCH] test+docs(simulation): address PR #164 review (both APPROVE)
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- Band-invariant test now sweeps high altitude (6 km) as well as sea level, so
  the lapse term + cold-end clamp are exercised jointly, not lat alone. (Hoshe #1, Tyre #3)
- Clarify the temp() helper comment: seed 0 is deterministic but still applies a
  constant non-zero nudge. (Hoshe #2)
- (Hoshe #3: confirmed tectonic_activity is genuinely absent from systems-schema.sql;
  the reader's 'not in schema' comment is accurate — no change.)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 server/src/atlas/region_profile.rs | 37 +++++++++++++++++-------------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/server/src/atlas/region_profile.rs b/server/src/atlas/region_profile.rs
index fa6b14c2f..b21e3d0f0 100644
--- a/server/src/atlas/region_profile.rs
+++ b/server/src/atlas/region_profile.rs
@@ -1171,7 +1171,8 @@ mod tests {
     // T-1024 / D-240 climate derivation tests — planet_class envelope model
     // -----------------------------------------------------------------------
 
-    /// Convenience: derive temperature with seed=0 for deterministic tests.
+    /// Convenience: derive temperature with a fixed seed (0) — deterministic, but
+    /// note seed 0 still applies its (constant, non-zero) nudge like any other seed.
     fn temp(planet_class: &str, atmosphere: &str, lat: f64, elev_km: f64) -> Option<f32> {
         let params = BodyParams {
             planet_class: Some(planet_class.into()),
@@ -1313,21 +1314,25 @@ mod tests {
             let (cold, warm) = climate.envelope(class);
             for atmo in &atmospheres {
                 for &lat in &latitudes {
-                    for seed in seeds {
-                        let params = BodyParams {
-                            planet_class: Some((*class).into()),
-                            atmosphere: Some((*atmo).into()),
-                            region_latitude_deg: lat,
-                            elevation_km: 0.0,
-                            ..Default::default()
-                        };
-                        let t = derive_temperature_c(&params, &climate, seed)
-                            .expect("non-airless body must have temperature");
-                        assert!(
-                            t >= cold && t <= warm,
-                            "class={class} atmo={atmo} lat={lat} seed={seed}: \
-                             temperature {t}°C outside band [{cold}, {warm}]"
-                        );
+                    // Sweep sea level AND high altitude so the lapse term + clamp
+                    // are exercised jointly against the cold end, not just lat alone.
+                    for elev in [0.0_f64, 6.0] {
+                        for seed in seeds {
+                            let params = BodyParams {
+                                planet_class: Some((*class).into()),
+                                atmosphere: Some((*atmo).into()),
+                                region_latitude_deg: lat,
+                                elevation_km: elev,
+                                ..Default::default()
+                            };
+                            let t = derive_temperature_c(&params, &climate, seed)
+                                .expect("non-airless body must have temperature");
+                            assert!(
+                                t >= cold && t <= warm,
+                                "class={class} atmo={atmo} lat={lat} elev={elev} seed={seed}: \
+                                 temperature {t}°C outside band [{cold}, {warm}]"
+                            );
+                        }
                     }
                 }
             }