randomized test generation using quickcheck

Cargo.lock

@@ -2,6 +2,127 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "cfg-if"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
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+checksum = "a19187fea3ac7e84da7dacf48de0c45d63c6a76f9490dae389aead16c243fce3"
+dependencies = [
+ "log",
+ "regex",
+]
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4567c8db10ae91089c99af84c68c38da3ec2f087c3f82960bcdbf3656b6f4d7"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
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+
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+
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+
 [[package]]
 name = "proximity"
 version = "0.1.0"
+dependencies = [
+ "quickcheck",
+]
+
+[[package]]
+name = "quickcheck"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "588f6378e4dd99458b60ec275b4477add41ce4fa9f64dcba6f15adccb19b50d6"
+dependencies = [
+ "env_logger",
+ "log",
+ "rand",
+]
+
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+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "rand_core",
+]
+
+[[package]]
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+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "regex"
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+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
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+name = "regex-automata"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "368758f23274712b504848e9d5a6f010445cc8b87a7cdb4d7cbee666c1288da3"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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Cargo.toml

@@ -4,3 +4,6 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+
+[dev-dependencies]
+quickcheck = "1.0.3"

src/linalg/vector.rs

@@ -7,14 +7,19 @@ impl<'a> Vector<'a> {
         self._repr.len()
     }
 
-    /// Computes the **SQUARED** L2 distance between two vectors. This is cheaper to compute than the regular L2 distance. This is typically useful when comparing two distances : dist(u,v) < dist(w, x) <=> dist(u,v) ** 2 < dist(w,x) ** 2
+    /// # Usage
+    /// Computes the **SQUARED** L2 distance between two vectors.
+    /// This is cheaper to compute than the regular L2 distance.
+    /// This is typically useful when comparing two distances :
+    ///
+    /// dist(u,v) < dist(w, x) ⇔ dist(u,v) ** 2 < dist(w,x) ** 2
     ///
     /// # Panics
     ///
-    /// Panics in debug mode if the two vectors have different lengths. In release mode, the longest vector will
-    /// be silently truncated.
+    /// Panics in debug mode if the two vectors have different lengths.
+    /// In release mode, the longest vector will be silently truncated.
     #[inline]
-    pub fn l2_dist_square(&self, other: &Vector<'a>) -> f32 {
+    pub fn l2_dist_squared(&self, other: &Vector<'a>) -> f32 {
         debug_assert!(self.len() == other.len());
 
         self._repr
@@ -27,9 +32,16 @@ impl<'a> Vector<'a> {
             .sum::<f32>()
     }
 
+    /// # Usage
+    /// Computes the L2 distance between two vectors.
+    ///
+    /// # Panics
+    ///
+    /// Panics in debug mode if the two vectors have different lengths.
+    /// In release mode, the longest vector will be silently truncated.
     #[inline]
     pub fn l2_dist(&self, other: &Vector<'a>) -> f32 {
-        self.l2_dist_square(other).sqrt()
+        self.l2_dist_squared(other).sqrt()
     }
 }
 
@@ -42,6 +54,7 @@ impl<'a> From<&'a [f32]> for Vector<'a> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use quickcheck::{QuickCheck, TestResult};
 
     const TOLERANCE: f32 = 1e-8;
 
@@ -49,15 +62,27 @@ mod tests {
         (target - actual).abs() < TOLERANCE
     }
 
-    fn check_l2(suspect: f32) -> bool {
+    fn is_valid_l2(suspect: f32) -> bool {
         suspect.is_finite() && suspect >= 0.0
     }
 
     #[test]
     fn self_sim_is_zero() {
-        let testvec = Vector::from([1.0, 2.0, 3.0, 1.5].as_slice());
-        let selfsim = testvec.l2_dist(&testvec);
-        assert!(check_l2(selfsim));
-        assert!(close(selfsim, 0.0));
+        fn qc_self_sim_is_zero(totest: Vec<f32>) -> TestResult {
+            if totest.iter().any(|x| !x.is_finite()) {
+                return TestResult::discard();
+            }
+            let testvec = Vector::from(&totest[..]);
+            let selfsim = testvec.l2_dist(&testvec);
+            let to_check = is_valid_l2(selfsim) && close(selfsim, 0.0);
+            return TestResult::from_bool(to_check);
+        }
+
+        QuickCheck::new()
+            .tests(10_000)
+            // force that less than 90% of tests are discarded due to precondition violations
+            // i.e. at least 10% of inputs should be valid so that we cover a good range
+            .min_tests_passed(1_000)
+            .quickcheck(qc_self_sim_is_zero as fn(Vec<f32>) -> TestResult);
     }
 }

src/main.rs

+#![allow(dead_code)]
 mod linalg;
 
 fn main() {