From 9997bbabb4cd3bbe172b65c1789d5e153996ea41 Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Tue, 7 May 2024 14:50:17 +0300
Subject: [PATCH] Test it!

---
 Cargo.toml      |  3 +++
 src/bin/flat.rs | 46 +++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index ca0a0e8..ddbdfe1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,3 +16,6 @@ glam = "0.27.0"
 flo_draw = "0.3.1"
 flo_canvas = "0.3.1"
 itertools-num = "0.1.3"
+
+[dev-dependencies]
+approx = "0.5.1"
diff --git a/src/bin/flat.rs b/src/bin/flat.rs
index 8c1eba5..f80add0 100644
--- a/src/bin/flat.rs
+++ b/src/bin/flat.rs
@@ -5,6 +5,9 @@ use glam::*;
 use riemann::{Decomp2, Metric, trace_iter};
 use crate::boundary::Loop;
 
+#[cfg(test)]
+use approx::assert_abs_diff_eq;
+
 pub fn main() {
 	let space = Coil {
 		scale: 3.0,
@@ -220,11 +223,44 @@ impl Rect {
 	fn b(&self) -> f32 { 2.0 * self.γ() - 1.0 }
 
 	fn root(&self, x: f32) -> f32 { ((2.0 * self.γ() - 1.0).powi(2) + 4.0 * (1.0 - self.γ()) * x / self.ri()).sqrt() }
-	fn d(&self, u: f32) -> f32 { 2.0 * self.a() * u.abs() + self.b() }
-	fn x(&self, u: f32) -> f32 { (self.a() * u.abs() + self.b()) * u }
-	fn u(&self, x: f32) -> f32 { 0.5 * self.ri() * (1.0 - 2.0 * self.γ() + self.root(x.abs())) / (1.0 - self.γ()) * x.signum() }
-	fn dx(&self, u: f32, du: f32) -> f32 { du * self.d(u) }
-	fn du(&self, x: f32, dx: f32) -> f32 { dx / self.d(self.u(x)) }
+	fn d(&self, u: f32) -> f32 { 2.0 * self.a() * u + self.b() }
+	pub fn x(&self, u: f32) -> f32 { (self.a() * u.abs() + self.b()) * u }
+	pub fn u(&self, x: f32) -> f32 { 0.5 * self.ri() * (1.0 - 2.0 * self.γ() + self.root(x.abs())) / (1.0 - self.γ()) * x.signum() }
+	pub fn dx(&self, u: f32, du: f32) -> f32 { du * self.d(u.abs()) }
+	pub fn du(&self, x: f32, dx: f32) -> f32 { dx / self.root(x.abs()) }
+}
+
+#[test]
+fn test_rect() {
+	let r = Rect {
+		outer_radius: 50.0,
+		inner_radius: 20.0,
+		external_halflength: 100.0,
+		internal_halflength: 10.0,
+	};
+	assert_abs_diff_eq!(r.x(r.internal_halflength), r.external_halflength, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.x(-r.internal_halflength), -r.external_halflength, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.u(r.external_halflength), r.internal_halflength, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.u(-r.external_halflength), -r.internal_halflength, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.u(r.x(1.0)), 1.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.u(r.x(5.0)), 5.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.u(r.x(-5.0)), -5.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.u(r.x(10.0)), 10.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.x(r.u(10.0)), 10.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.x(r.u(50.0)), 50.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.x(r.u(-50.0)), -50.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.x(r.u(100.0)), 100.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.d(r.u(10.0)), r.root(10.0), epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.d(r.u(50.0)), r.root(50.0), epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.d(r.u(100.0)), r.root(100.0), epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.du(10.0, r.dx(r.u(10.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.du(50.0, r.dx(r.u(50.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.du(-50.0, r.dx(r.u(-50.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.du(100.0, r.dx(r.u(100.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.dx(1.0, r.du(r.x(1.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.dx(5.0, r.du(r.x(5.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.dx(-5.0, r.du(r.x(-5.0), 3.0)), 3.0, epsilon = 1.0e-5);
+	assert_abs_diff_eq!(r.dx(10.0, r.du(r.x(10.0), 3.0)), 3.0, epsilon = 1.0e-5);
 }
 
 impl Metric for Rect {