contract/test-harness: Set fixed-difficulty=1 mining

Cargo.lock

@@ -1833,6 +1833,7 @@ dependencies = [
  "darkfi_deployooor_contract",
  "darkfi_money_contract",
  "log",
+ "num-bigint",
  "rand 0.8.5",
  "simplelog",
  "sled",

src/contract/test-harness/Cargo.toml

@@ -14,6 +14,7 @@ darkfi_money_contract = {path = "../money", features = ["client", "no-entrypoint
 darkfi_consensus_contract = {path = "../consensus", features = ["client", "no-entrypoint"]}
 darkfi_deployooor_contract = {path = "../deployooor", features = ["client", "no-entrypoint"]}
 
+num-bigint = "0.4.4"
 blake3 = "1.5.0"
 bs58 = "0.5.0"
 log = "0.4.20"

src/contract/test-harness/src/lib.rs

@@ -46,6 +46,7 @@ use darkfi_sdk::{
     pasta::pallas,
 };
 use log::{info, warn};
+use num_bigint::BigUint;
 use rand::rngs::OsRng;
 
 mod benchmarks;
@@ -163,7 +164,7 @@ impl Wallet {
             3,
             1,
             90,
-            None,
+            Some(BigUint::from(1_u8)),
             genesis_block.clone(),
             0,
             faucet_pubkeys.to_vec(),