tests: add deterministic chain generation unittest fixture

src/test/util/setup_common.cpp

@@ -199,14 +199,43 @@ TestingSetup::TestingSetup(const std::string& chainName, const std::vector<const
     }
 }
 
-TestChain100Setup::TestChain100Setup()
+TestChain100Setup::TestChain100Setup(bool deterministic)
 {
+    m_deterministic = deterministic;
+
+    if (m_deterministic) {
+        SetMockTime(1598887952);
+        constexpr std::array<unsigned char, 32> vchKey = {
+            {
+                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
+            }
+        };
+        coinbaseKey.Set(vchKey.begin(), vchKey.end(), false);
+    } else {
+        coinbaseKey.MakeNewKey(true);
+    }
+
     // Generate a 100-block chain:
-    coinbaseKey.MakeNewKey(true);
+    this->mineBlocks(COINBASE_MATURITY);
+
+    if (m_deterministic) {
+        LOCK(::cs_main);
+        assert(
+            m_node.chainman->ActiveChain().Tip()->GetBlockHash().ToString() ==
+            "49c95db1e470fed04496d801c9d8fbb78155d2c7f855232c918823d2c17d0cf6");
+    }
+}
+
+void TestChain100Setup::mineBlocks(int num_blocks)
+{
     CScript scriptPubKey = CScript() << ToByteVector(coinbaseKey.GetPubKey()) << OP_CHECKSIG;
-    for (int i = 0; i < COINBASE_MATURITY; i++) {
+    for (int i = 0; i < num_blocks; i++)
+    {
         std::vector<CMutableTransaction> noTxns;
         CBlock b = CreateAndProcessBlock(noTxns, scriptPubKey);
+        if (m_deterministic) {
+            SetMockTime(GetTime() + 1);
+        }
         m_coinbase_txns.push_back(b.vtx[0]);
     }
 }
@@ -234,6 +263,9 @@ CBlock TestChain100Setup::CreateAndProcessBlock(const std::vector<CMutableTransa
 TestChain100Setup::~TestChain100Setup()
 {
     gArgs.ForceSetArg("-segwitheight", "0");
+    if (m_deterministic) {
+        SetMockTime(0);
+    }
 }
 
 CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CMutableTransaction& tx) const

src/test/util/setup_common.h

@@ -78,7 +78,6 @@ struct BasicTestingSetup {
     explicit BasicTestingSetup(const std::string& chainName = CBaseChainParams::MAIN, const std::vector<const char*>& extra_args = {});
     ~BasicTestingSetup();
 
-private:
     const fs::path m_path_root;
 };
 
@@ -112,7 +111,7 @@ class CScript;
  * Testing fixture that pre-creates a 100-block REGTEST-mode block chain
  */
 struct TestChain100Setup : public RegTestingSetup {
-    TestChain100Setup();
+    TestChain100Setup(bool deterministic = false);
 
     /**
      * Create a new block with just given transactions, coinbase paying to
@@ -121,12 +120,21 @@ struct TestChain100Setup : public RegTestingSetup {
     CBlock CreateAndProcessBlock(const std::vector<CMutableTransaction>& txns,
                                  const CScript& scriptPubKey);
 
+    //! Mine a series of new blocks on the active chain.
+    void mineBlocks(int num_blocks);
+
     ~TestChain100Setup();
 
+    bool m_deterministic;
     std::vector<CTransactionRef> m_coinbase_txns; // For convenience, coinbase transactions
     CKey coinbaseKey; // private/public key needed to spend coinbase transactions
 };
 
+
+struct TestChain100DeterministicSetup : public TestChain100Setup {
+    TestChain100DeterministicSetup() : TestChain100Setup(true) { }
+};
+
 class CTxMemPoolEntry;
 
 struct TestMemPoolEntryHelper