changes

crates/domain/tests/metric/hrv_test.rs

@@ -0,0 +1,17 @@
+use domain::metric::Hrv;
+
+#[test]
+fn a_variability_of_zero_is_rejected() {
+    assert!(Hrv::new(0).is_err());
+}
+
+#[test]
+fn a_variability_beyond_any_recorded_reading_is_rejected() {
+    assert!(Hrv::new(301).is_err());
+}
+
+#[test]
+fn the_boundaries_of_variability_are_valid() {
+    assert_eq!(Hrv::new(1).unwrap().value(), 1);
+    assert_eq!(Hrv::new(300).unwrap().value(), 300);
+}