From 6ec81bd17e18eed3de705a07a86bd1bf239e6ba3 Mon Sep 17 00:00:00 2001
From: Daniel Schadt <kingdread@gmx.de>
Date: Tue, 26 Aug 2025 21:49:03 +0200
Subject: add first tests

---
 Cargo.lock            | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hittekaart/Cargo.toml |  1 +
 hittekaart/src/gpx.rs | 33 +++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 0594ef5..d67ed63 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -558,6 +558,12 @@ version = "0.31.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "07e28edb80900c19c28f1072f2e8aeca7fa06b23cd4169cefe1af5aa3260783f"
 
+[[package]]
+name = "glob"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"
+
 [[package]]
 name = "half"
 version = "2.6.0"
@@ -615,6 +621,7 @@ dependencies = [
  "num-traits",
  "rayon",
  "roxmltree",
+ "rstest",
  "rusqlite",
  "thiserror",
 ]
@@ -1310,6 +1317,12 @@ version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
 
+[[package]]
+name = "relative-path"
+version = "1.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba39f3699c378cd8970968dcbff9c43159ea4cfbd88d43c00b22f2ef10a435d2"
+
 [[package]]
 name = "roxmltree"
 version = "0.18.1"
@@ -1319,6 +1332,32 @@ dependencies = [
  "xmlparser",
 ]
 
+[[package]]
+name = "rstest"
+version = "0.26.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f5a3193c063baaa2a95a33f03035c8a72b83d97a54916055ba22d35ed3839d49"
+dependencies = [
+ "rstest_macros",
+]
+
+[[package]]
+name = "rstest_macros"
+version = "0.26.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c845311f0ff7951c5506121a9ad75aec44d083c31583b2ea5a30bcb0b0abba0"
+dependencies = [
+ "cfg-if",
+ "glob",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "relative-path",
+ "rustc_version",
+ "syn",
+ "unicode-ident",
+]
+
 [[package]]
 name = "rusqlite"
 version = "0.29.0"
@@ -1339,6 +1378,15 @@ version = "0.1.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "989e6739f80c4ad5b13e0fd7fe89531180375b18520cc8c82080e4dc4035b84f"
 
+[[package]]
+name = "rustc_version"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfcb3a22ef46e85b45de6ee7e79d063319ebb6594faafcf1c225ea92ab6e9b92"
+dependencies = [
+ "semver",
+]
+
 [[package]]
 name = "rusttype"
 version = "0.9.3"
@@ -1379,6 +1427,12 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "semver"
+version = "1.0.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56e6fa9c48d24d85fb3de5ad847117517440f6beceb7798af16b4a87d616b8d0"
+
 [[package]]
 name = "serde"
 version = "1.0.219"
diff --git a/hittekaart/Cargo.toml b/hittekaart/Cargo.toml
index 62ec6e9..651aec4 100644
--- a/hittekaart/Cargo.toml
+++ b/hittekaart/Cargo.toml
@@ -27,3 +27,4 @@ thiserror = "2.0.12"
 
 [dev-dependencies]
 criterion = "0.5.0"
+rstest = { version = "0.26.1", default-features = false }
diff --git a/hittekaart/src/gpx.rs b/hittekaart/src/gpx.rs
index 86cb88b..8bd076d 100644
--- a/hittekaart/src/gpx.rs
+++ b/hittekaart/src/gpx.rs
@@ -60,6 +60,8 @@ impl Coordinates {
         let ymax = 2u64.pow(zoom) as f64 * HEIGHT;
 
         let lambda = self.longitude.to_radians().clamp(-max_lon, max_lon);
+        // The coordinate +180° is the same as -180°, so we want to map them to the same point
+        let lambda = if lambda == PI { -PI } else { lambda };
         let phi = self.latitude.to_radians().clamp(-max_lat, max_lat);
         let phi = (phi.tan() + (1.0 / phi.cos())).ln();
         let x = xmax / (2.0 * PI) * (lambda + PI);
@@ -171,3 +173,34 @@ pub fn extract_from_file<P: AsRef<Path>>(
     };
     extract_from_str(&content)
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use rstest::*;
+
+    #[rstest]
+    #[case((0.0, 0.0), 0, (128, 128))]
+    #[case((-180.0, 0.0), 0, (0, 128))]
+    #[case((180.0, 0.0), 0, (0, 128))]
+    #[case((179.99, 0.0), 0, (255, 128))]
+    #[case((0.0, 90.0), 0, (128, 0))]
+    #[case((0.0, -90.0), 0, (128, 255))]
+    #[case((0.0, 0.0), 4, (2048, 2048))]
+    #[case((-180.0, 0.0), 4, (0, 2048))]
+    #[case((180.0, 0.0), 4, (0, 2048))]
+    #[case((179.99, 0.0), 4, (4095, 2048))]
+    #[case((0.0, 90.0), 4, (2048, 0))]
+    #[case((0.0, -90.0), 4, (2048, 4095))]
+    #[case((-90.0, 0.0), 0, (64, 128))]
+    #[case((90.0, 0.0), 0, (192, 128))]
+    // Example taken from
+    // https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Example:_Convert_a_GPS_coordinate_to_a_pixel_position_in_a_Web_Mercator_tile
+    #[case((139.7006793, 35.6590699), 18, (232798 * 256 + 238, 103246 * 256 + 105))]
+    fn web_mercator(#[case] input: (f64, f64), #[case] zoom: u32, #[case] expected: (u64, u64)) {
+        assert_eq!(
+            Coordinates::new(input.0, input.1).web_mercator(zoom),
+            expected
+        );
+    }
+}
-- 
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