diff --git a/clovers/Cargo.toml b/clovers/Cargo.toml
index dca5e57b..0097ede0 100644
--- a/clovers/Cargo.toml
+++ b/clovers/Cargo.toml
@@ -32,6 +32,7 @@ tracing = { version = "0.1.40", optional = true }
 
 [dev-dependencies]
 divan = "0.1.11"
+proptest = "1"
 
 [[bench]]
 name = "random"
diff --git a/clovers/tests/wavelength.rs b/clovers/tests/wavelength.rs
new file mode 100644
index 00000000..533f1639
--- /dev/null
+++ b/clovers/tests/wavelength.rs
@@ -0,0 +1,22 @@
+use clovers::wavelength::*;
+use proptest::prelude::*;
+
+proptest! {
+  #[test]
+  fn converts_all_wavelengths(lambda in SPECTRUM) {
+      let _ = wavelength_into_xyz(lambda);
+  }
+}
+
+proptest! {
+  #[test]
+  fn rotates_all_wavelengths(lambda in SPECTRUM) {
+      let mut waves = rotate_wavelength(lambda);
+      prop_assert_eq!(waves[0], lambda);
+      waves.sort();
+      let [a, b, c, d] = waves;
+      let diff = a.abs_diff(b);
+      prop_assert_eq!(diff, b.abs_diff(c));
+      prop_assert_eq!(diff, c.abs_diff(d));
+  }
+}