Add tests

Author: daxpedda

hash2curve/src/hash2field/expand_msg/xmd.rs

@@ -171,6 +171,31 @@ mod test {
     use hex_literal::hex;
     use sha2::Sha256;
 
+    #[test]
+    fn edge_cases() {
+        fn generate() -> ExpanderXmd<'static, Sha256> {
+            <ExpandMsgXmd<Sha256> as ExpandMsg<U4>>::expand_message(
+                &[b"test message"],
+                &[b"test DST"],
+                NonZero::new(64).unwrap(),
+            )
+            .unwrap()
+        }
+
+        assert_eq!(generate().fill_bytes(&mut [0; 0]), Ok(0));
+        assert_eq!(generate().fill_bytes(&mut [0; 1]), Ok(1));
+        assert_eq!(generate().fill_bytes(&mut [0; 64]), Ok(64));
+        assert_eq!(generate().fill_bytes(&mut [0; 65]), Ok(64));
+
+        let mut expander = generate();
+        assert_eq!(expander.fill_bytes(&mut [0; 0]), Ok(0));
+        assert_eq!(expander.fill_bytes(&mut [0; 32]), Ok(32));
+        assert_eq!(expander.fill_bytes(&mut [0; 0]), Ok(0));
+        assert_eq!(expander.fill_bytes(&mut [0; 31]), Ok(31));
+        assert_eq!(expander.fill_bytes(&mut [0; 2]), Ok(1));
+        assert_eq!(expander.fill_bytes(&mut [0; 1]), Err(Error));
+    }
+
     fn assert_message<HashT>(
         msg: &[u8],
         domain: &Domain<'_, HashT::OutputSize>,

hash2curve/src/hash2field/expand_msg/xof.rs

@@ -103,6 +103,29 @@ mod test {
     use hex_literal::hex;
     use sha3::Shake128;
 
+    #[test]
+    fn edge_cases() {
+        fn generate() -> ExpandMsgXof<Shake128> {
+            <ExpandMsgXof<Shake128> as ExpandMsg<U16>>::expand_message(
+                &[b"test message"],
+                &[b"test DST"],
+                NonZero::new(64).unwrap(),
+            )
+            .unwrap()
+        }
+
+        assert_eq!(generate().fill_bytes(&mut [0; 0]), Ok(0));
+        assert_eq!(generate().fill_bytes(&mut [0; 1]), Ok(1));
+        assert_eq!(generate().fill_bytes(&mut [0; 64]), Ok(64));
+        assert_eq!(generate().fill_bytes(&mut [0; 65]), Ok(64));
+
+        let mut expander = generate();
+        assert_eq!(expander.fill_bytes(&mut [0; 0]), Ok(0));
+        assert_eq!(expander.fill_bytes(&mut [0; 1]), Ok(1));
+        assert_eq!(expander.fill_bytes(&mut [0; 64]), Ok(63));
+        assert_eq!(expander.fill_bytes(&mut [0; 1]), Err(Error));
+    }
+
     fn assert_message(msg: &[u8], domain: &Domain<'_, U32>, len_in_bytes: u16, bytes: &[u8]) {
         let msg_len = msg.len();
         assert_eq!(msg, &bytes[..msg_len]);