feat: add test with poseidon

Cargo.toml

@@ -7,3 +7,5 @@ edition = "2021"
 hex-literal = "0.3.4"
 tiny-keccak = { version = "2.0.2", features = ["keccak"] }
 sled = "0.34.7"
+rln = { git = "https://github.com/vacp2p/zerokit", rev = "490206a" }
+ark-serialize = "0.3.0"

tests/poseidon.rs

@@ -0,0 +1,97 @@
+use pmtree::*;
+
+use rln::circuit::Fr;
+use rln::poseidon_hash::poseidon_hash;
+
+use std::collections::HashMap;
+use std::io::Cursor;
+use std::str::{self, FromStr};
+
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
+
+struct MemoryDB(HashMap<DBKey, Value>);
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+struct PoseidonHash;
+
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+struct MyFr(Fr);
+
+impl Hasher for PoseidonHash {
+    type Fr = MyFr;
+
+    fn default_leaf() -> Self::Fr {
+        MyFr(Fr::from(0))
+    }
+
+    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
+        MyFr(poseidon_hash(
+            &inputs.iter().map(|&x| x.0).collect::<Vec<_>>(),
+        ))
+    }
+}
+
+impl From<Vec<u8>> for MyFr {
+    fn from(v: Vec<u8>) -> Self {
+        let c = Cursor::new(v);
+        let f = Fr::deserialize(c).unwrap();
+        MyFr(f)
+    }
+}
+
+impl From<MyFr> for Vec<u8> {
+    fn from(v: MyFr) -> Self {
+        let mut buf = vec![];
+
+        Fr::serialize(&v.0, &mut buf).unwrap();
+
+        buf
+    }
+}
+
+impl Database for MemoryDB {
+    fn new(_dbpath: &str) -> Result<Self> {
+        Ok(MemoryDB(HashMap::new()))
+    }
+
+    fn load(_dbpath: &str) -> Result<Self> {
+        Err(Error("Cannot load in-memory DB".to_string()))
+    }
+
+    fn get(&self, key: DBKey) -> Result<Option<Value>> {
+        Ok(self.0.get(&key).cloned())
+    }
+
+    fn put(&mut self, key: DBKey, value: Value) -> Result<()> {
+        self.0.insert(key, value);
+
+        Ok(())
+    }
+}
+
+#[test]
+fn poseidon_memory() -> Result<()> {
+    let mut mt = MerkleTree::<MemoryDB, PoseidonHash>::new(2, "abacaba")?;
+
+    assert_eq!(mt.capacity(), 4);
+    assert_eq!(mt.depth(), 2);
+
+    let leaves = vec![
+        MyFr(Fr::from_str("12345").unwrap()),
+        MyFr(Fr::from_str("67891").unwrap()),
+        MyFr(Fr::from_str("23456").unwrap()),
+        MyFr(Fr::from_str("78912").unwrap()),
+    ];
+
+    mt.update_next(leaves[0])?;
+
+    // for &leaf in &leaves {
+    //     mt.update_next(leaf)?;
+    // }
+
+    // for (i, leaf) in leaves.iter().enumerate() {
+    //     assert!(mt.verify(leaf, &mt.proof(i)?));
+    // }
+
+    Ok(())
+}