From 8258c4c0076bb5f27efdc117a04b27fcd6dd00b2 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Tue, 8 Sep 2020 11:55:40 +1000
Subject: [PATCH] test: some sanity checks for consensus logic

---
 src/test/pow_tests.cpp | 47 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/src/test/pow_tests.cpp b/src/test/pow_tests.cpp
index 0f9872f434b..ca49b89ad84 100644
--- a/src/test/pow_tests.cpp
+++ b/src/test/pow_tests.cpp
@@ -135,4 +135,51 @@ BOOST_AUTO_TEST_CASE(GetBlockProofEquivalentTime_test)
     }
 }
 
+void sanity_check_chainparams(std::string chainName)
+{
+    const auto chainParams = CreateChainParams(chainName);
+    const auto consensus = chainParams->GetConsensus();
+
+    // hash genesis is correct
+    BOOST_CHECK_EQUAL(consensus.hashGenesisBlock, chainParams->GenesisBlock().GetHash());
+
+    // target timespan is an even multiple of spacing
+    BOOST_CHECK_EQUAL(consensus.nPowTargetTimespan % consensus.nPowTargetSpacing, 0);
+
+    // genesis nBits is positive, doesn't overflow and is lower than powLimit
+    arith_uint256 pow_compact;
+    bool neg, over;
+    pow_compact.SetCompact(chainParams->GenesisBlock().nBits, &neg, &over);
+    BOOST_CHECK(!neg && pow_compact != 0);
+    BOOST_CHECK(!over);
+    BOOST_CHECK(UintToArith256(consensus.powLimit) >= pow_compact);
+
+    // check max target * 4*nPowTargetTimespan doesn't overflow -- see pow.cpp:CalculateNextWorkRequired()
+    if (!consensus.fPowNoRetargeting) {
+        arith_uint256 targ_max("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+        targ_max /= consensus.nPowTargetTimespan*4;
+        BOOST_CHECK(UintToArith256(consensus.powLimit) < targ_max);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_MAIN_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::MAIN);
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_REGTEST_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::REGTEST);
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_TESTNET_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::TESTNET);
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_SIGNET_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::SIGNET);
+}
+
 BOOST_AUTO_TEST_SUITE_END()