Clean up some getblocktemplate difficulty code and tests

zebra-rpc/src/methods/tests/snapshot/get_block_template_rpcs.rs

@@ -106,6 +106,7 @@ pub async fn test_responses<State, ReadState>(
     let fake_cur_time = DateTime32::from(1654008617);
     // nu5 block time + 123
     let fake_max_time = DateTime32::from(1654008728);
+    let fake_difficulty = CompactDifficulty::from(ExpandedDifficulty::from(U256::one()));
 
     let (mock_chain_tip, mock_chain_tip_sender) = MockChainTip::new();
     mock_chain_tip_sender.send_best_tip_height(fake_tip_height);
@@ -181,7 +182,7 @@ pub async fn test_responses<State, ReadState>(
             .expect_request_that(|req| matches!(req, ReadRequest::ChainInfo))
             .await
             .respond(ReadResponse::ChainInfo(GetBlockTemplateChainInfo {
-                expected_difficulty: CompactDifficulty::from(ExpandedDifficulty::from(U256::one())),
+                expected_difficulty: fake_difficulty,
                 tip_height: fake_tip_height,
                 tip_hash: fake_tip_hash,
                 cur_time: fake_cur_time,
@@ -235,7 +236,7 @@ pub async fn test_responses<State, ReadState>(
             .expect_request_that(|req| matches!(req, ReadRequest::ChainInfo))
             .await
             .respond(ReadResponse::ChainInfo(GetBlockTemplateChainInfo {
-                expected_difficulty: CompactDifficulty::from(ExpandedDifficulty::from(U256::one())),
+                expected_difficulty: fake_difficulty,
                 tip_height: fake_tip_height,
                 tip_hash: fake_tip_hash,
                 cur_time: fake_cur_time,

zebra-rpc/src/methods/tests/vectors.rs

@@ -953,6 +953,7 @@ async fn rpc_getblocktemplate_mining_address(use_p2pkh: bool) {
     let fake_cur_time = DateTime32::from(1654008617);
     // nu5 block time + 123
     let fake_max_time = DateTime32::from(1654008728);
+    let fake_difficulty = CompactDifficulty::from(ExpandedDifficulty::from(U256::one()));
 
     let (mock_chain_tip, mock_chain_tip_sender) = MockChainTip::new();
     mock_chain_tip_sender.send_best_tip_height(fake_tip_height);
@@ -976,7 +977,7 @@ async fn rpc_getblocktemplate_mining_address(use_p2pkh: bool) {
             .expect_request_that(|req| matches!(req, ReadRequest::ChainInfo))
             .await
             .respond(ReadResponse::ChainInfo(GetBlockTemplateChainInfo {
-                expected_difficulty: CompactDifficulty::from(ExpandedDifficulty::from(U256::one())),
+                expected_difficulty: fake_difficulty,
                 tip_height: fake_tip_height,
                 tip_hash: fake_tip_hash,
                 cur_time: fake_cur_time,

zebra-state/src/response.rs

@@ -166,16 +166,14 @@ pub struct GetBlockTemplateChainInfo {
     /// Depends on the `tip_hash`.
     pub history_tree: Arc<zebra_chain::history_tree::HistoryTree>,
 
-    // Data derived from the state tip and recent blocks.
-    //
-    /// The expected difficulty of the candidate block.
-    /// Depends on the `tip_hash`.
-    pub expected_difficulty: CompactDifficulty,
-
     // Data derived from the state tip and recent blocks, and the current local clock.
     //
+    /// The expected difficulty of the candidate block.
+    /// Depends on the `tip_hash`, and the local clock on testnet.
+    pub expected_difficulty: CompactDifficulty,
+
     /// The current system time, adjusted to fit within `min_time` and `max_time`.
-    /// Depends on the local clock and the `tip_hash`.
+    /// Always depends on the local clock and the `tip_hash`.
     pub cur_time: DateTime32,
 
     /// The mininimum time the miner can use in this block.

zebra-state/src/service/read/difficulty.rs

@@ -227,12 +227,13 @@ fn difficulty_time_and_history_tree(
         network,
         relevant_data.iter().cloned(),
     );
+    let expected_difficulty = difficulty_adjustment.expected_difficulty_threshold();
 
     let mut result = GetBlockTemplateChainInfo {
         tip_hash,
         tip_height,
         history_tree,
-        expected_difficulty: difficulty_adjustment.expected_difficulty_threshold(),
+        expected_difficulty,
         cur_time,
         min_time,
         max_time,