test: add prop tests for keccak

lib/crypto/src/keccak.rs

@@ -45,3 +45,108 @@ impl Hash for [u8; 32] {
         state.update(self);
     }
 }
+
+#[cfg(all(test, feature = "std"))]
+mod tests {
+    use proptest::prelude::*;
+
+    use super::*;
+
+    proptest! {
+        #[test]
+        fn sequential_updates_match_concatenated(data1: Vec<u8>, data2: Vec<u8>) {
+            let builder = KeccakBuilder;
+
+            let mut hasher1 = builder.build_hasher();
+            hasher1.update(&data1);
+            hasher1.update(&data2);
+            let result1 = hasher1.finalize();
+
+            let mut hasher2 = builder.build_hasher();
+            let mut concatenated = data1.clone();
+            concatenated.extend_from_slice(&data2);
+            hasher2.update(concatenated);
+            let result2 = hasher2.finalize();
+
+            prop_assert_eq!(result1, result2);
+        }
+
+        #[test]
+        fn split_updates_match_full_update(data: Vec<u8>, split_point: usize) {
+            if data.is_empty() {
+                return Ok(());
+            }
+
+            let builder = KeccakBuilder;
+            let split_at = split_point % data.len();
+
+            let mut hasher1 = builder.build_hasher();
+            hasher1.update(&data[..split_at]);
+            hasher1.update(&data[split_at..]);
+            let result1 = hasher1.finalize();
+
+            let mut hasher2 = builder.build_hasher();
+            hasher2.update(&data);
+            let result2 = hasher2.finalize();
+
+            prop_assert_eq!(result1, result2);
+        }
+
+        #[test]
+        fn multiple_hasher_instances_are_consistent(
+            data1: Vec<u8>,
+            data2: Vec<u8>,
+        ) {
+            let builder = KeccakBuilder;
+
+            let mut hasher1 = builder.build_hasher();
+            hasher1.update(&data1);
+            hasher1.update(&data2);
+            let result1 = hasher1.finalize();
+
+            let mut hasher2 = builder.build_hasher();
+            hasher2.update(&data1);
+            hasher2.update(&data2);
+            let result2 = hasher2.finalize();
+
+            prop_assert_eq!(result1, result2);
+        }
+
+        #[test]
+        fn output_is_always_32_bytes(data: Vec<u8>) {
+            let builder = KeccakBuilder;
+            let mut hasher = builder.build_hasher();
+            hasher.update(&data);
+            let result = hasher.finalize();
+            assert_eq!(result.len(), 32);
+        }
+    }
+
+    #[test]
+    fn test_empty_input() {
+        let builder = KeccakBuilder;
+        let mut hasher = builder.build_hasher();
+        hasher.update(&[]);
+        let result = hasher.finalize();
+        let expected: [u8; 32] = [
+            0xc5, 0xd2, 0x46, 0x01, 0x86, 0xf7, 0x23, 0x3c, 0x92, 0x7e, 0x7d,
+            0xb2, 0xdc, 0xc7, 0x03, 0xc0, 0xe5, 0x00, 0xb6, 0x53, 0xca, 0x82,
+            0x27, 0x3b, 0x7b, 0xfa, 0xd8, 0x04, 0x5d, 0x85, 0xa4, 0x70,
+        ];
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_known_hash() {
+        let builder = KeccakBuilder;
+        let mut hasher = builder.build_hasher();
+        hasher.update(b"hello");
+        let result = hasher.finalize();
+        let expected: [u8; 32] = [
+            0x1c, 0x8a, 0xff, 0x95, 0x06, 0x85, 0xc2, 0xed, 0x4b, 0xc3, 0x17,
+            0x4f, 0x34, 0x72, 0x28, 0x7b, 0x56, 0xd9, 0x51, 0x7b, 0x9c, 0x94,
+            0x81, 0x27, 0x31, 0x9a, 0x09, 0xa7, 0xa3, 0x6d, 0xea, 0xc8,
+        ];
+        assert_eq!(result, expected);
+    }
+}