From e86e211bed0ed190c7ce605eac0a20acacb85082 Mon Sep 17 00:00:00 2001
From: Stephen Waits <steve@waits.net>
Date: Tue, 7 Feb 2023 21:37:21 -0700
Subject: [PATCH] test: add property tests to HeightVector

Which also helped me fix a bug (using is_sign_negative() when we actually are okay with -0.0).

Signed-off-by: Stephen Waits <steve@waits.net>
---
 proptest-regressions/height_vector.txt | 10 ++++
 src/height_vector.rs                   | 65 ++++++++++++++++++++++++--
 2 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 proptest-regressions/height_vector.txt

diff --git a/proptest-regressions/height_vector.txt b/proptest-regressions/height_vector.txt
new file mode 100644
index 0000000..493a7d2
--- /dev/null
+++ b/proptest-regressions/height_vector.txt
@@ -0,0 +1,10 @@
+# Seeds for failure cases proptest has generated in the past. It is
+# automatically read and these particular cases re-run before any
+# novel cases are generated.
+#
+# It is recommended to check this file in to source control so that
+# everyone who runs the test benefits from these saved cases.
+cc 4a5cb6ca844d5306203ae00a99375c83a20ddf4ca427f0ae0b541697efa3d9b7 # shrinks to x = 0.0, y = 0.0, h = -4.122071e-39
+cc 38ed1e2c313317809f5469d856d2c1c61e4851c64a156cd1bdd0757fa7c77128 # shrinks to x = 0.0, y = -0.0, h = 0.0, m = -0.0
+cc b7d1b5e9fe3e33066b583c4532865373179972e9b5786ecc62438f23bc939e87 # shrinks to x = -0.0, y = 0.0, h = -3.448118e-33, m = -0.0
+cc 3c4fc4f21c82ffe5bcbc740ca9ab598e0894226acb86a3046a3a24cbbcdbf8e6 # shrinks to x = 0.0, y = 0.0, h = -0.0
diff --git a/src/height_vector.rs b/src/height_vector.rs
index 4b95dcb..a3a720e 100644
--- a/src/height_vector.rs
+++ b/src/height_vector.rs
@@ -118,7 +118,7 @@ impl<const N: usize> HeightVector<N> {
     /// In this case, valid means the height is positive, and none of the components are NaN or
     /// Inf.
     pub(crate) fn is_invalid(&self) -> bool {
-        self.1.is_sign_negative() || self.1.is_nan() || self.1.is_infinite() || self.0.is_invalid()
+        self.0.is_invalid() || self.1.is_nan() || self.1.is_infinite() || self.1 < 0.0
     }
 }
 
@@ -193,9 +193,68 @@ impl<const N: usize> Mul<f32> for HeightVector<N> {
 //
 #[cfg(test)]
 mod tests {
-    use assert_approx_eq::assert_approx_eq;
-
     use super::*;
+    use assert_approx_eq::assert_approx_eq;
+    use proptest::prelude::*;
+
+    proptest! {
+        #[test]
+        fn proptest_len(x: f32, y: f32, h: f32) {
+            let len = ((x*x) + (y*y)).sqrt() + h.abs();
+            let a = HeightVector::<2>::from(([x,y],h));
+            if x.is_nan() || x.is_infinite() || y.is_nan() || y.is_infinite() || h.is_nan() || h.is_infinite() || h < 0.0 {
+                // we should've gottne a random univ vector here
+                assert_approx_eq!(a.len(), 1.0);
+            } else {
+                // `HeightVector` we created from proptest values should be valid and have a length
+                assert_eq!(a.len(), len);
+            }
+        }
+
+        #[test]
+        fn proptest_add(x0 in -1_000_000_000..1_000_000_000i32, y0 in -1_000_000_000..1_000_000_000i32, h0 in 0..1_000_000_000i32, x1 in -1_000_000_000..1_000_000_000i32, y1 in -1_000_000_000..1_000_000_000i32, h1 in 0..1_000_000i32) {
+            // convert our integer range inputs to f32s
+            let (fx0,fy0,fh0) = (x0 as f32 / 1_000.0, y0 as f32 / 1_000.0, h0 as f32 / 1_000.0);
+            let (fx1,fy1,fh1) = (x1 as f32 / 1_000.0, y1 as f32 / 1_000.0, h1 as f32 / 1_000.0);
+
+            let a = HeightVector::<2>::from(([fx0 ,fy0 ],fh0 ));
+            let b = HeightVector::<2>::from(([fx1 ,fy1 ],fh1 ));
+            let c = a+b;
+            assert_eq!(c.0[0], fx0 + fx1);
+            assert_eq!(c.0[1], fy0 + fy1);
+            assert_eq!(c.1, fh0 + fh1);
+        }
+
+        #[test]
+        fn proptest_sub(x0 in -1_000_000_000..1_000_000_000i32, y0 in -1_000_000_000..1_000_000_000i32, h0 in 0..1_000_000_000i32, x1 in -1_000_000_000..1_000_000_000i32, y1 in -1_000_000_000..1_000_000_000i32, h1 in 0..1_000_000i32) {
+            // convert our integer range inputs to f32s
+            let (fx0,fy0,fh0) = (x0 as f32 / 1_000.0, y0 as f32 / 1_000.0, h0 as f32 / 1_000.0);
+            let (fx1,fy1,fh1) = (x1 as f32 / 1_000.0, y1 as f32 / 1_000.0, h1 as f32 / 1_000.0);
+
+            let a = HeightVector::<2>::from(([fx0 ,fy0 ],fh0 ));
+            let b = HeightVector::<2>::from(([fx1 ,fy1 ],fh1 ));
+            let c = a-b;
+            assert_eq!(c.0[0], fx0 - fx1);
+            assert_eq!(c.0[1], fy0 - fy1);
+            assert_eq!(c.1, fh0 + fh1);
+        }
+
+        #[test]
+        fn proptest_mul(x in -1_000_000_000..1_000_000_000i32, y in -1_000_000_000..1_000_000_000i32, h in 0..1_000_000_000i32, m in -1_000_000_000..1_000_000_000i32) {
+            // convert our integer range inputs to f32s
+            let (fx,fy,fh,fm) = (x as f32 / 1_000.0, y as f32 / 1_000.0, h as f32 / 1_000.0, m as f32 / 1_000.0);
+
+            let a = HeightVector::<2>::from(([fx, fy], fh));
+            let b = a * fm;
+            if fm < 0.0 {
+                assert_approx_eq!(b.len(), 1.0)
+            } else {
+                assert_eq!(b.0[0], fx * fm);
+                assert_eq!(b.0[1], fy * fm);
+                assert_eq!(b.1, fh * fm);
+            }
+        }
+    }
 
     #[test]
     fn test_len() {