diff --git a/src/game/engine/scenes/tests/iter_7q_worldmap_visual_proof.gd b/src/game/engine/scenes/tests/iter_7q_worldmap_visual_proof.gd
index e80111e5..b85da808 100644
--- a/src/game/engine/scenes/tests/iter_7q_worldmap_visual_proof.gd
+++ b/src/game/engine/scenes/tests/iter_7q_worldmap_visual_proof.gd
@@ -40,6 +40,18 @@ func _ready() -> void:
 	var world_map: Node = WorldMapScene.instantiate()
 	add_child(world_map)
 
+	# WorldMap itself is a Node2D, but its ViewportWindowManager child is a
+	# Control that anchors full-rect to its parent. Without an explicit size
+	# the Control resolves to 0×0 (Node2D parent), the SubViewportContainer
+	# stretch can't inflate, and the composited frame renders black. Push the
+	# 1920×1080 size manually after mount so all descendants size correctly.
+	var vwm: Control = world_map.get_node_or_null("ViewportWindowManager") as Control
+	if vwm != null:
+		vwm.size = Vector2(1920, 1080)
+		# Re-trigger the size-resolved code path that wires the SubViewport.
+		if vwm.has_method("_sync_background_size"):
+			vwm.call("_sync_background_size")
+
 	# Wait for rendering to settle
 	for _i: int in range(30):
 		await get_tree().process_frame