diff --git a/tests/common/mod.rs b/tests/common/mod.rs
index 49660db..10a6150 100644
--- a/tests/common/mod.rs
+++ b/tests/common/mod.rs
@@ -145,12 +145,18 @@ pub fn assert_band_length(
     board: &Board<impl AccessMesadata>,
     source: &str,
     target: &str,
-    length: f64,
-    epsilon: f64,
+    expected_length: f64,
+    rel_err: f64,
 ) {
     let band = board.band_between_pins(source, target).unwrap();
     let band_length = band.0.ref_(board.layout().drawing()).length();
-    assert!((band_length - length).abs() < epsilon);
+    assert!(
+        (band_length - expected_length).abs() < expected_length * rel_err,
+        "band_length = {}, expected_length = {}, epsilon = {}",
+        band_length,
+        expected_length,
+        rel_err
+    );
 }
 
 fn unionfind(autorouter: &mut Autorouter<impl AccessMesadata>) -> UnionFind<NodeIndex<usize>> {
diff --git a/tests/single_layer.rs b/tests/single_layer.rs
index 4c583a8..12361af 100644
--- a/tests/single_layer.rs
+++ b/tests/single_layer.rs
@@ -38,7 +38,7 @@ fn test_tht_diode_bridge_rectifier() {
 
     common::assert_single_layer_groundless_autoroute(&mut autorouter, "F.Cu");
     //common::assert_number_of_conncomps(&mut autorouter, 4);
-    common::assert_band_length(autorouter.board(), "J2-2", "D4-2", 15500.0, 0.5);
+    common::assert_band_length(autorouter.board(), "J2-2", "D4-2", 15900.0, 0.01);
 
     let mut invoker = Invoker::new(autorouter);
     let result = invoker.execute(Command::PlaceVia(ViaWeight {