feat: support mock mining in epoch 3.0

Author: obycode

testnet/stacks-node/src/nakamoto_node/miner.rs

@@ -411,6 +411,10 @@ impl BlockMinerThread {
                 },
             )?;
 
+        if self.config.get_node_config(false).mock_mining {
+            return Ok((reward_set, Vec::new()));
+        }
+
         *attempts += 1;
         let signature = coordinator.begin_sign_v0(
             new_block,

testnet/stacks-node/src/nakamoto_node/relayer.rs

@@ -412,7 +412,7 @@ impl RelayerThread {
         }
 
         let directive = if sn.sortition {
-            if won_sortition {
+            if won_sortition || self.config.get_node_config(false).mock_mining {
                 MinerDirective::BeginTenure {
                     parent_tenure_start: committed_index_hash,
                     burnchain_tip: sn,