chore: remove new method from hasher trait & implement test

src/hasher.rs

@@ -5,9 +5,6 @@ pub trait Hasher {
     /// Native type for the hash-function
     type Fr: Copy + Eq + Default + From<Value> + Into<Value>;
 
-    /// Creates new hash-function instance
-    fn new() -> Self;
-
     /// Outputs the default leaf (Fr::default())
     fn default_leaf() -> Self::Fr;
 

tests/memory_keccak.rs

@@ -1,7 +1,7 @@
 use hex_literal::hex;
 use pmtree::*;
 use std::collections::HashMap;
-use tiny_keccak::Keccak;
+use tiny_keccak::{Hasher as _, Keccak};
 
 pub struct MemoryDB(HashMap<DBKey, Value>);
 pub struct MyKeccak(Keccak);
@@ -10,52 +10,55 @@ pub struct MyKeccak(Keccak);
 pub struct MyFr([u8; 32]);
 
 impl Database for MemoryDB {
-    fn new(dbpath: &str) -> Self {
-        todo!()
+    fn new(_dbpath: &str) -> Self {
+        MemoryDB(HashMap::new())
     }
 
-    fn load(dbpath: &str) -> Self {
-        todo!()
+    fn load(_dbpath: &str) -> Self {
+        panic!("Cannot load in-memory db!")
     }
 
     fn get(&self, key: DBKey) -> Option<Value> {
-        todo!()
+        self.0.get(&key).cloned()
     }
 
     fn put(&mut self, key: DBKey, value: Value) {
-        todo!()
+        self.0.insert(key, value);
     }
 
     fn delete(&mut self, key: DBKey) {
-        todo!()
+        self.0.remove(&key);
     }
 }
 
 impl From<Vec<u8>> for MyFr {
     fn from(v: Vec<u8>) -> Self {
-        todo!()
+        let v = v.try_into().unwrap();
+        MyFr(v)
     }
 }
 
 impl From<MyFr> for Vec<u8> {
     fn from(v: MyFr) -> Self {
-        todo!()
+        v.0.to_vec()
     }
 }
 
 impl Hasher for MyKeccak {
     type Fr = MyFr;
 
-    fn new() -> Self {
-        todo!()
-    }
-
     fn default_leaf() -> Self::Fr {
-        todo!()
+        MyFr([0; 32])
     }
 
     fn hash(input: &[Self::Fr]) -> Self::Fr {
-        todo!()
+        let mut output = [0; 32];
+        let mut hasher = Keccak::v256();
+        for element in input {
+            hasher.update(&element.0);
+        }
+        hasher.finalize(&mut output);
+        MyFr(output)
     }
 }