Test for the bugfix

src/bin/flat/tube/mod.rs

@@ -296,4 +296,58 @@ mod coords {
 			}
 		}
 	}
+
+	#[cfg(test)]
+	mod test {
+		use super::{Location, Tube, MapperOuter};
+		use glam::{Mat2, vec2};
+		use itertools_num::linspace;
+
+		#[test]
+		fn test_mapper_outer() {
+			let mapper = Tube {
+				inner_radius: 30.0,
+				outer_radius: 50.0,
+				internal_halflength: 100.0,
+				external_halflength: 300.0,
+			};
+			// straight
+			for x in linspace(-60., 60., 20) {
+				for y in linspace(-320., 320., 20) {
+					assert_eq!(mapper.global_to_outer(Location { pos: vec2(x, y), rot: Mat2::IDENTITY }).pos.x, x);
+				}
+			}
+			// symmetrical
+			for x in linspace(0., 60., 20) {
+				for y in linspace(0., 320., 20) {
+					let pp = mapper.global_to_outer(Location { pos: vec2(x, y), rot: Mat2::IDENTITY }).pos;
+					let np = mapper.global_to_outer(Location { pos: vec2(-x, y), rot: Mat2::IDENTITY }).pos;
+					let pn = mapper.global_to_outer(Location { pos: vec2(x, -y), rot: Mat2::IDENTITY }).pos;
+					let nn = mapper.global_to_outer(Location { pos: vec2(-x, -y), rot: Mat2::IDENTITY }).pos;
+					assert_eq!(np, vec2(-pp.x, pp.y));
+					assert_eq!(pn, vec2(pp.x, -pp.y));
+					assert_eq!(nn, vec2(-pp.x, -pp.y));
+				}
+			}
+			// clean boundary
+			for x in linspace(50., 60., 20) {
+				for y in linspace(0., 320., 20) {
+					assert_eq!(mapper.global_to_outer(Location { pos: vec2(x, y), rot: Mat2::IDENTITY }).pos.y, y);
+				}
+			}
+			for x in linspace(0., 60., 20) {
+				for y in linspace(300., 320., 20) {
+					assert_eq!(mapper.global_to_outer(Location { pos: vec2(x, y), rot: Mat2::IDENTITY }).pos.y, y);
+				}
+			}
+			// accelerating
+			for x in linspace(-29., 29., 20) {
+				for y in linspace(1., 299., 20) {
+					let v = mapper.global_to_outer(Location { pos: vec2(x, y), rot: Mat2::IDENTITY }).pos.y;
+					assert!(v > 200.0);
+					assert!(v > y);
+				}
+			}
+		}
+	}
 }