message: mockchain: Implement FromStr for Hash
diff: @@ -7,6 +7,8 @@ use chain_crypto::{
  AsymmetricKey, KeyEvolvingSignatureAlgorithm, SigningAlgorithm, VerificationAlgorithm,
  };
  +use std::str::FromStr;
  +
  pub type SpendingPublicKey = crypto::PublicKey<crypto::Ed25519Extended>;
  pub type SpendingSecretKey = crypto::SecretKey<crypto::Ed25519Extended>;
  pub type SpendingSignature<T> = crypto::Signature<T, crypto::Ed25519Extended>;
  @@ -217,6 +219,13 @@ impl std::fmt::Display for Hash {
  }
  }
  +impl FromStr for Hash {
  + type Err = crypto::hash::Error;
  + fn from_str(s: &str) -> Result<Self, Self::Err> {
  + Ok(Hash(crypto::Blake2b256::from_str(s)?))
  + }
  +}
  +
  #[cfg(test)]
  pub mod test {
  use super::*;
  