1 files changed, 164 insertions, 0 deletions
diff --git a/tvix/eval/src/properties.rs b/tvix/eval/src/properties.rs
new file mode 100644
index 0000000000..45c1cdfce9
--- /dev/null
+++ b/tvix/eval/src/properties.rs
@@ -0,0 +1,164 @@
+//! Macros that generate proptest test suites checking laws of stdlib traits
+
+/// Generate a suite of tests to check the laws of the [`Eq`] impl for the given type
+macro_rules! eq_laws {
+    ($ty: ty) => {
+        eq_laws!(
+            #[strategy(::proptest::arbitrary::any::<$ty>())]
+            $ty,
+            Default::default()
+        );
+    };
+    ($ty: ty, $config: expr) => {
+        eq_laws!(
+            #[strategy(::proptest::arbitrary::any::<$ty>())]
+            $ty,
+            $config
+        );
+    };
+    (#[$meta: meta] $ty: ty, $config: expr) => {
+        #[allow(clippy::eq_op)]
+        mod eq {
+            use test_strategy::proptest;
+
+            use super::*;
+
+            #[proptest($config)]
+            fn reflexive(#[$meta] x: $ty) {
+                assert!(x == x);
+            }
+
+            #[proptest($config)]
+            fn symmetric(#[$meta] x: $ty, #[$meta] y: $ty) {
+                assert_eq!(x == y, y == x);
+            }
+
+            #[proptest($config)]
+            fn transitive(#[$meta] x: $ty, #[$meta] y: $ty, #[$meta] z: $ty) {
+                if x == y && y == z {
+                    assert!(x == z);
+                }
+            }
+        }
+    };
+}
+
+/// Generate a suite of tests to check the laws of the [`Ord`] impl for the given type
+macro_rules! ord_laws {
+    ($ty: ty) => {
+        ord_laws!(
+            #[strategy(::proptest::arbitrary::any::<$ty>())]
+            $ty,
+            Default::default()
+        );
+    };
+    ($ty: ty, $config: expr) => {
+        ord_laws!(
+            #[strategy(::proptest::arbitrary::any::<$ty>())]
+            $ty,
+            $config
+        );
+    };
+    (#[$meta: meta] $ty: ty, $config: expr) => {
+        mod ord {
+            use test_strategy::proptest;
+
+            use super::*;
+
+            #[proptest($config)]
+            fn partial_cmp_matches_cmp(#[$meta] x: $ty, #[$meta] y: $ty) {
+                assert_eq!(x.partial_cmp(&y), Some(x.cmp(&y)));
+            }
+
+            #[proptest($config)]
+            fn dual(#[$meta] x: $ty, #[$meta] y: $ty) {
+                if x < y {
+                    assert!(y > x);
+                }
+                if y < x {
+                    assert!(x > y);
+                }
+            }
+
+            #[proptest($config)]
+            fn le_transitive(#[$meta] x: $ty, #[$meta] y: $ty, #[$meta] z: $ty) {
+                if x < y && y < z {
+                    assert!(x < z)
+                }
+            }
+
+            #[proptest($config)]
+            fn gt_transitive(#[$meta] x: $ty, #[$meta] y: $ty, #[$meta] z: $ty) {
+                if x > y && y > z {
+                    assert!(x > z)
+                }
+            }
+
+            #[proptest($config)]
+            fn trichotomy(#[$meta] x: $ty, #[$meta] y: $ty) {
+                let less = x < y;
+                let greater = x > y;
+                let eq = x == y;
+
+                if less {
+                    assert!(!greater);
+                    assert!(!eq);
+                }
+
+                if greater {
+                    assert!(!less);
+                    assert!(!eq);
+                }
+
+                if eq {
+                    assert!(!less);
+                    assert!(!greater);
+                }
+            }
+        }
+    };
+}
+
+/// Generate a test to check the laws of the [`Hash`] impl for the given type
+macro_rules! hash_laws {
+    ($ty: ty) => {
+        hash_laws!(
+            #[strategy(::proptest::arbitrary::any::<$ty>())]
+            $ty,
+            Default::default()
+        );
+    };
+    ($ty: ty, $config: expr) => {
+        hash_laws!(
+            #[strategy(::proptest::arbitrary::any::<$ty>())]
+            $ty,
+            $config
+        );
+    };
+    (#[$meta: meta] $ty: ty, $config: expr) => {
+        mod hash {
+            use test_strategy::proptest;
+
+            use super::*;
+
+            #[proptest($config)]
+            fn matches_eq(#[$meta] x: $ty, #[$meta] y: $ty) {
+                let hash = |x: &$ty| {
+                    use std::hash::Hasher;
+
+                    let mut hasher = ::std::collections::hash_map::DefaultHasher::new();
+                    x.hash(&mut hasher);
+                    hasher.finish()
+                };
+
+                if x == y {
+                    assert_eq!(hash(&x), hash(&y));
+                }
+            }
+        }
+    };
+}
+
+pub(crate) use eq_laws;
+pub(crate) use hash_laws;
+pub(crate) use ord_laws;