test(dash): G1 difficulty/vardiff parity KAT — share-diff floor + per-share min_work oracle pin

.github/workflows/build.yml

@@ -102,7 +102,7 @@ jobs:
                     core_test sharechain_test share_test btc_share_test \
                     test_threading test_weights \
                     test_header_chain test_mempool test_template_builder \
-                    test_doge_chain test_compact_blocks test_dash_x11_kat test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_stratum_binding test_dash_job_notify_roundtrip test_dash_cb_payee test_dash_stratum_notify_roundtrip test_dash_poolnode_messages test_dash_peer test_dash_share_tracker test_dash_node test_dash_share_messages test_dash_stratum_extranonce_split test_dash_stratum_submit_reassembly \
+                    test_doge_chain test_compact_blocks test_dash_x11_kat test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_stratum_binding test_dash_job_notify_roundtrip test_dash_cb_payee test_dash_stratum_notify_roundtrip test_dash_poolnode_messages test_dash_peer test_dash_share_tracker test_dash_node test_dash_share_messages test_dash_stratum_extranonce_split test_dash_stratum_submit_reassembly test_dash_difficulty_parity \
                     test_multiaddress_pplns test_pplns_stress \
                     test_hash_link test_decay_pplns \
                     test_pplns_consensus \
@@ -252,7 +252,7 @@ jobs:
                     test_threading test_weights \
                     test_header_chain test_mempool test_template_builder \
                     test_doge_chain test_compact_blocks test_dash_x11_kat \
-                    test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_stratum_binding test_dash_job_notify_roundtrip test_dash_cb_payee test_dash_stratum_notify_roundtrip test_dash_poolnode_messages test_dash_peer test_dash_share_tracker test_dash_node test_dash_share_messages test_dash_stratum_extranonce_split test_dash_stratum_submit_reassembly \
+                    test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_stratum_binding test_dash_job_notify_roundtrip test_dash_cb_payee test_dash_stratum_notify_roundtrip test_dash_poolnode_messages test_dash_peer test_dash_share_tracker test_dash_node test_dash_share_messages test_dash_stratum_extranonce_split test_dash_stratum_submit_reassembly test_dash_difficulty_parity \
                     test_hash_link test_decay_pplns \
                     test_pplns_consensus \
                     test_v36_script_sorting test_v36_cross_impl_refhash \

test/CMakeLists.txt

@@ -347,6 +347,20 @@ if (BUILD_TESTING AND GTest_FOUND)
     target_link_libraries(test_dash_stratum_binding PRIVATE c2pool_payout c2pool_hashrate c2pool_merged_mining)  # OBJECT-lib SCC direct-naming (#22/#39)
     gtest_add_tests(test_dash_stratum_binding "" AUTO)
 
+    # DASH G1 difficulty / vardiff PARITY KAT: share-diff floor byte-exactness +
+    # per-share min_work (target_to_average_attempts) oracle pin. Header-only over
+    # core/target_utils + config_pool; pure, socket-free. Mirrors the work_target
+    # link set.
+    add_executable(test_dash_difficulty_parity test_dash_difficulty_parity.cpp)
+    target_link_libraries(test_dash_difficulty_parity PRIVATE
+        GTest::gtest_main GTest::gtest
+        dash_x11 core
+        nlohmann_json::nlohmann_json
+        ${Boost_LIBRARIES}
+    )
+    target_link_libraries(test_dash_difficulty_parity PRIVATE c2pool_payout c2pool_hashrate c2pool_merged_mining)  # OBJECT-lib SCC direct-naming (#22/#39)
+    gtest_add_tests(test_dash_difficulty_parity "" AUTO)
+
     # share_init_verify gentx hash_link byte-parity vs oracle (coinbase_payload
     # VarStr prefix). Header-only over the dash_x11 + core link set; mirrors the
     # test_dash_conformance link set.

test/test_dash_difficulty_parity.cpp

@@ -0,0 +1,110 @@
+// DASH G1 difficulty / vardiff PARITY KAT.
+//
+// Pins the DASH sharechain difficulty floor and its per-share work accounting
+// to oracle-EXACT arithmetic from frstrtr/p2pool-dash (networks/dash.py +
+// bitcoin/data.py). Two independent surfaces:
+//
+//   1. dash::SharechainConfig::max_target() — the share-diff floor (easiest allowed
+//      share target). Byte-exact to the oracle _DIFF1_TARGET (mainnet) and the
+//      2**256//2**20-1 testnet floor.
+//   2. chain::target_to_average_attempts(target) == 2**256 // (target+1) — the
+//      per-share MINIMUM work that ShareIndex accumulates from m_max_bits
+//      (share_chain.hpp:228). This is the quantity that drives cumulative-work
+//      / APS retarget parity across the chain.
+//
+// Every expected value is derived INDEPENDENTLY from the oracle integer formula
+// (see the derive comment on each vector), NOT read back from the SUT — a true
+// byte-parity pin, not a tautology. The cross-coin APS-over-chain accumulation
+// is already pinned LTC-instantiated in test_compute_share_target.cpp; this KAT
+// pins the DASH-specific config floor + the min_work-per-share derivation those
+// oracle numbers differ on (p2pool-dash, not p2pool-ltc).
+//
+// Pure / socket-free / node-free: no VM200/201 dashd, no live sharechain.
+// Runs on every Linux x86_64 ctest.
+
+#include <gtest/gtest.h>
+
+#include <core/target_utils.hpp>
+#include <core/uint256.hpp>
+#include <impl/dash/config_pool.hpp>
+
+namespace {
+uint288 U288(const char* h) { uint288 t; t.SetHex(h); return t; }
+}  // namespace
+
+// ── 1. share-diff floor byte-exactness (networks/dash.py SHARE_MAX_TARGET) ──
+
+// mainnet floor == 0xFFFF * 2**208 (standard bdiff difficulty-1 target).
+TEST(DashDifficultyParity, MainnetMaxTargetFloorExact)
+{
+    dash::SharechainConfig::is_testnet = false;
+    EXPECT_EQ(dash::SharechainConfig::max_target().GetHex(),
+        "00000000ffff0000000000000000000000000000000000000000000000000000");
+}
+
+// testnet floor == 2**256 // 2**20 - 1. Derive (python3):
+//   "%064x" % (2**256 // 2**20 - 1)
+TEST(DashDifficultyParity, TestnetMaxTargetFloorExact)
+{
+    dash::SharechainConfig::is_testnet = true;
+    EXPECT_EQ(dash::SharechainConfig::max_target().GetHex(),
+        "00000fffffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
+    dash::SharechainConfig::is_testnet = false;
+}
+
+// ── 2. per-share min_work = target_to_average_attempts(floor) ───────────────
+//
+// ShareIndex(share).min_work = target_to_average_attempts(bits_to_target(
+//   m_max_bits))  (share_chain.hpp:228). At the difficulty floor that reduces
+// to target_to_average_attempts(max_target()).
+
+// mainnet: attempts = 2**256 // (0xFFFF*2**208 + 1). Derive (python3):
+//   (2**256)//(0xFFFF*(2**208)+1)  ==  4295032833  ==  0x100010001
+TEST(DashDifficultyParity, MainnetPerShareMinWorkExact)
+{
+    dash::SharechainConfig::is_testnet = false;
+    uint288 attempts = chain::target_to_average_attempts(dash::SharechainConfig::max_target());
+    EXPECT_EQ(attempts.GetHex(), U288("100010001").GetHex());
+    EXPECT_TRUE(attempts == static_cast<uint64_t>(4295032833ULL));
+}
+
+// testnet: attempts = 2**256 // (2**256//2**20). Derive (python3):
+//   (2**256)//((2**256//2**20-1)+1)  ==  1048576  ==  2**20  ==  0x100000
+TEST(DashDifficultyParity, TestnetPerShareMinWorkExact)
+{
+    dash::SharechainConfig::is_testnet = true;
+    uint288 attempts = chain::target_to_average_attempts(dash::SharechainConfig::max_target());
+    EXPECT_EQ(attempts.GetHex(), U288("100000").GetHex());
+    EXPECT_TRUE(attempts == static_cast<uint64_t>(1048576ULL));
+    dash::SharechainConfig::is_testnet = false;
+}
+
+// ── 3. ShareIndex min_work accumulation identity (dash floor) ───────────────
+//
+// Over N equal-floor shares the accumulated min_work == per_share * N, the same
+// identity DeltaCache maintains (test_compute_share_target DeltaCacheAfterPruning,
+// LTC). Pinned here with DASH-floor numbers so a config-floor regression is
+// caught in the DASH lane directly.
+TEST(DashDifficultyParity, MainnetMinWorkAccumulationIdentity)
+{
+    dash::SharechainConfig::is_testnet = false;
+    uint288 per_share = chain::target_to_average_attempts(dash::SharechainConfig::max_target());
+    // N=199 (default real_chain window sample). Derive (python3):
+    //   4295032833 * 199 == 854711533767
+    uint288 acc = per_share * static_cast<uint64_t>(199);
+    EXPECT_TRUE(acc == static_cast<uint64_t>(854711533767ULL));
+}
+
+// ── 4. floor bits roundtrip (m_max_bits <-> floor target) ───────────────────
+//
+// ShareIndex derives min_work from m_max_bits via bits_to_target; the floor
+// must survive the compact encode/decode used to carry it on the wire.
+TEST(DashDifficultyParity, MainnetFloorBitsRoundtrip)
+{
+    dash::SharechainConfig::is_testnet = false;
+    uint256 floor = dash::SharechainConfig::max_target();
+    uint32_t bits = chain::target_to_bits_upper_bound(floor);
+    uint256 decoded = chain::bits_to_target(bits);
+    EXPECT_EQ(decoded, floor);          // exact roundtrip at the standard floor
+    EXPECT_EQ(bits >> 24, 0x1du);       // 0xFFFF*2**208 -> exponent 0x1d (29 bytes)
+}