diff --git a/src/bin/flat/main.rs b/src/bin/flat/main.rs
index 0073387..58fdee2 100644
--- a/src/bin/flat/main.rs
+++ b/src/bin/flat/main.rs
@@ -9,9 +9,6 @@ use riemann::{Tens2, Decomp2, Metric, trace_iter};
 use shape::Shape;
 use Subspace::{Boundary, Inner, Outer};
 
-#[cfg(test)]
-use approx::assert_abs_diff_eq;
-
 const DT: f32 = 0.1;
 
 fn draw_loop(gc: &mut Vec<Draw>, mut pts: impl Iterator<Item=Vec2>) {
@@ -701,42 +698,6 @@ mod fns {
 	}
 }
 
-#[test]
-fn test_tube() {
-	let t = Tube {
-		outer_radius: 50.0,
-		inner_radius: 20.0,
-		external_halflength: 100.0,
-		internal_halflength: 10.0,
-	};
-	assert_abs_diff_eq!(t.y(t.internal_halflength), t.external_halflength, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.y(-t.internal_halflength), -t.external_halflength, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.v(t.external_halflength), t.internal_halflength, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.v(-t.external_halflength), -t.internal_halflength, epsilon = 1.0e-5);
-
-	assert_abs_diff_eq!(t.dy(t.internal_halflength), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dy(-t.internal_halflength), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dv(t.external_halflength), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dv(-t.external_halflength), 1.0, epsilon = 1.0e-5);
-
-	assert_abs_diff_eq!(t.v(t.y(1.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.v(t.y(5.0)), 5.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.v(t.y(-5.0)), -5.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.v(t.y(10.0)), 10.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.y(t.v(10.0)), 10.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.y(t.v(50.0)), 50.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.y(t.v(-50.0)), -50.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.y(t.v(100.0)), 100.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dv(10.0) * t.dy(t.v(10.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dv(50.0) * t.dy(t.v(50.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dv(-50.0) * t.dy(t.v(-50.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dv(100.0) * t.dy(t.v(100.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dy(1.0) * t.dv(t.y(1.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dy(5.0) * t.dv(t.y(5.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dy(-5.0) * t.dv(t.y(-5.0)), 1.0, epsilon = 1.0e-5);
-	assert_abs_diff_eq!(t.dy(10.0) * t.dv(t.y(10.0)), 1.0, epsilon = 1.0e-5);
-}
-
 trait FloatExt2 {
 	fn lerp(&self, t: f32) -> f32;
 	fn inverse_lerp(&self, y: f32) -> f32;