diff --git a/src/game/engine/tests/unit/test_smoke.gd b/src/game/engine/tests/unit/test_smoke.gd
index 0f9e5bc7..f6124f28 100644
--- a/src/game/engine/tests/unit/test_smoke.gd
+++ b/src/game/engine/tests/unit/test_smoke.gd
@@ -3,22 +3,32 @@ extends GutTest
 ## Dataset is minimal (only game.json, vocabulary.json, climate_spec.json).
 ## Full data tests belong in the milestones that add that data.
 
+const ClimateScript: GDScript = preload("res://engine/src/modules/climate/climate.gd")
+
 
 func before_all() -> void:
 	# GUT runs without main.gd, so data must be loaded explicitly.
 	DataLoader.load_theme("age-of-dwarves")
+	DataLoader.load_world("earth")
 	ThemeVocabulary.load_vocabulary("age-of-dwarves")
 
 
 func test_data_loader_has_climate_spec() -> void:
+	# climate_spec.json lives under the world manifest (loaded via load_world).
 	var spec: Dictionary = DataLoader.get_climate_spec()
-	assert_false(spec.is_empty(), "climate_spec.json must be loaded")
+	assert_false(spec.is_empty(), "climate_spec.json must be loaded from world manifest")
 
 
 func test_theme_vocabulary_loaded() -> void:
 	assert_true(ThemeVocabulary.has_key("power"), "vocabulary must have 'power' key")
-	assert_true(ThemeVocabulary.has_key("discipline"), "vocabulary must have 'discipline' key")
-	assert_true(ThemeVocabulary.has_key("social_policy_title"), "vocabulary must have 'social_policy_title' key")
+	assert_true(
+		ThemeVocabulary.has_key("discipline"),
+		"vocabulary must have 'discipline' key",
+	)
+	assert_true(
+		ThemeVocabulary.has_key("social_policy_title"),
+		"vocabulary must have 'social_policy_title' key",
+	)
 
 
 func test_theme_vocabulary_active_theme() -> void:
@@ -27,15 +37,14 @@ func test_theme_vocabulary_active_theme() -> void:
 
 
 func test_climate_instantiates() -> void:
-	const ClimateScript: GDScript = preload("res://engine/src/modules/climate/climate.gd")
 	var climate: RefCounted = ClimateScript.new()
 	assert_not_null(climate, "Climate must instantiate")
 
 
 func test_climate_loads_params_from_defaults() -> void:
-	const ClimateScript: GDScript = preload("res://engine/src/modules/climate/climate.gd")
 	var climate: RefCounted = ClimateScript.new()
-	# No climate_params.json in M0 — _ensure_params falls back to built-in defaults
-	climate._ensure_params()
-	assert_true(climate._params_loaded, "Climate._params_loaded must be true after _ensure_params()")
-	assert_false(climate._params.is_empty(), "Climate._params must be populated (from defaults)")
+	# Iter 7: physics moved to Rust. _ensure_rust() loads params/spec/terrain into
+	# the Rust GdClimatePhysics instance and flips _params_loaded once initialized.
+	climate._ensure_rust()
+	assert_true(climate._params_loaded, "Climate._params_loaded must be true after _ensure_rust()")
+	assert_not_null(climate._rust, "Climate._rust (GdClimatePhysics) must be instantiated")