Derive ship scrap drop from threat

src/test/CombatSystemTest.cpp

@@ -14,6 +14,7 @@
 #include "HealthComponent.h"
 #include "HqProxyComponent.h"
 #include "ModuleOwnerComponent.h"
+#include "ScrapDataComponent.h"
 #include "ScrapSystem.h"
 #include "ShipSystem.h"
 #include "Simulation.h"
@@ -406,24 +407,19 @@ TEST_CASE("CombatSystem: scrap is spawned on ship death", "[combat]")
 {
     Simulation sim(loadConfig(), 42);
 
-    const ShipDef* droppingDef = nullptr;
-    for (const ShipDef& def : sim.config().ships.ships)
-    {
-        if (def.loot.scrapDrop > 0)
-        {
-            droppingDef = &def;
-            break;
-        }
-    }
-    REQUIRE(droppingDef != nullptr);
-
-    const entt::entity ship = sim.ships().spawn(droppingDef->id, 1,
+    // Scrap dropped on death is derived from the ship's as-built threat cost
+    // (REQ-RES-SCRAP-DROP): round(threat * scrap_per_threat). The interceptor's
+    // threat is 59.0 and the test config sets scrap_per_threat = 1.0, so it drops
+    // round(59.0 * 1.0) = 59 scrap.
+    const entt::entity ship = sim.ships().spawn("interceptor", 1,
         QVector2D(10.0f, 10.0f));
     sim.admin().get<HealthComponent>(ship).hp = -1.0f;
 
     sim.tick();
 
-    REQUIRE(!sim.scraps().allScrapInfo().empty());
+    const std::vector<ScrapInfo> scraps = sim.scraps().allScrapInfo();
+    REQUIRE(scraps.size() == 1);
+    CHECK(sim.admin().get<ScrapDataComponent>(scraps[0].entity).amount == 59);
 }
 
 TEST_CASE("CombatSystem: HQ death sets game over", "[combat]")

src/test/ConfigLoaderTest.cpp

@@ -78,6 +78,7 @@ TEST_CASE("ConfigLoader loads the committed bin/config/ configs end-to-end", "[c
     REQUIRE(cfg.world.push.bossAdvanceSeconds == Approx(60.0));
     REQUIRE(cfg.world.orbitFactor == Approx(0.8));
     REQUIRE(cfg.world.rallyOrbitRadius_tiles == Approx(5.0));
+    REQUIRE(cfg.world.scrapPerThreat == Approx(1.0));
 
     // Spot-check that a config-derived formula computes as expected.
     // threat_rate_formula = "x": evaluates to the input value.
@@ -167,6 +168,7 @@ TEST_CASE("Missing field in world.toml is rejected with the field path", "[confi
 height_tiles = 60
 refund_percentage = 75
 scrap_despawn_seconds = 30
+scrap_per_threat = 0.01
 tile_size_m = 10
 belt_speed_mps = 20
 starting_building_blocks = 100
@@ -217,6 +219,7 @@ TEST_CASE("Malformed formula in world.toml is rejected with field identification
 height_tiles = 60
 refund_percentage = 75
 scrap_despawn_seconds = 30
+scrap_per_threat = 0.01
 tile_size_m = 10
 belt_speed_mps = 20
 starting_building_blocks = 100
@@ -268,6 +271,7 @@ TEST_CASE("Inverted wave gap range is rejected", "[config]")
 height_tiles = 60
 refund_percentage = 75
 scrap_despawn_seconds = 30
+scrap_per_threat = 0.01
 tile_size_m = 10
 belt_speed_mps = 20
 

src/test/ThreatCostCalculatorTest.cpp

@@ -41,16 +41,15 @@ TEST_CASE("ThreatCostCalculator: assembler takes max across recipes", "[threat]"
     CHECK(table.itemThreat.at("circuit_board") == Approx(28.0));
 }
 
-TEST_CASE("ThreatCostCalculator: scrap threat from cheapest ship", "[threat]")
+TEST_CASE("ThreatCostCalculator: scrap threat is 1 / scrap_per_threat", "[threat]")
 {
     const GameConfig cfg = loadConfig();
     const ThreatCostTable& table = cfg.threatCosts;
 
-    // Cheapest ship by scrap_drop is interceptor (scrap_drop=2).
-    // Interceptor threat: 10 + iron_ingot(4)*3 + circuit_board(28)*1
-    //   + laser_cannon(5 + iron_ingot(4)*1) = 10 + 12 + 28 + 9 = 59.0
-    // scrapThreat = 59.0 / 2 = 29.5
-    CHECK(table.scrapThreat == Approx(29.5));
+    // REQ-THREAT-SCRAP: scrap threat is the constant 1 / world.scrap_per_threat.
+    // The test config sets scrap_per_threat = 1.0, so scrapThreat = 1.0.
+    CHECK(table.scrapThreat == Approx(1.0 / cfg.world.scrapPerThreat));
+    CHECK(table.scrapThreat == Approx(1.0));
 }
 
 TEST_CASE("ThreatCostCalculator: reprocessing-only item threat", "[threat]")
@@ -59,8 +58,8 @@ TEST_CASE("ThreatCostCalculator: reprocessing-only item threat", "[threat]")
     const ThreatCostTable& table = cfg.threatCosts;
 
     // advanced_alloy: reprocessing recipe with scrap*5, duration 3.0, probability 0.1
-    // (29.5 * 5 + 3.0) / 0.1 = 1505.0
-    CHECK(table.itemThreat.at("advanced_alloy") == Approx(1505.0));
+    // scrapThreat = 1.0 (= 1 / scrap_per_threat), so (1.0 * 5 + 3.0) / 0.1 = 80.0
+    CHECK(table.itemThreat.at("advanced_alloy") == Approx(80.0));
 }
 
 TEST_CASE("ThreatCostCalculator: ship threat with default modules", "[threat]")