fuzz: Limit mocktime to MTP in tx_pool targets

This is needed for the next commit to generate blocks.

Also, apply the same mocking strategies to both targets.

Author: MarcoFalke

src/test/fuzz/tx_pool.cpp

@@ -77,13 +77,21 @@ void SetMempoolConstraints(ArgsManager& args, FuzzedDataProvider& fuzzed_data_pr
                      ToString(fuzzed_data_provider.ConsumeIntegralInRange<unsigned>(0, 999)));
 }
 
+void MockTime(FuzzedDataProvider& fuzzed_data_provider, const CChainState& chainstate)
+{
+    const auto time = ConsumeTime(fuzzed_data_provider,
+                                  chainstate.m_chain.Tip()->GetMedianTimePast() + 1,
+                                  std::numeric_limits<decltype(chainstate.m_chain.Tip()->nTime)>::max());
+    SetMockTime(time);
+}
+
 FUZZ_TARGET_INIT(tx_pool_standard, initialize_tx_pool)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     const auto& node = g_setup->m_node;
     auto& chainstate = node.chainman->ActiveChainstate();
 
-    SetMockTime(ConsumeTime(fuzzed_data_provider));
+    MockTime(fuzzed_data_provider, chainstate);
     SetMempoolConstraints(*node.args, fuzzed_data_provider);
 
     // All RBF-spendable outpoints
@@ -163,7 +171,7 @@ FUZZ_TARGET_INIT(tx_pool_standard, initialize_tx_pool)
         }();
 
         if (fuzzed_data_provider.ConsumeBool()) {
-            SetMockTime(ConsumeTime(fuzzed_data_provider));
+            MockTime(fuzzed_data_provider, chainstate);
         }
         if (fuzzed_data_provider.ConsumeBool()) {
             SetMempoolConstraints(*node.args, fuzzed_data_provider);
@@ -254,6 +262,10 @@ FUZZ_TARGET_INIT(tx_pool, initialize_tx_pool)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     const auto& node = g_setup->m_node;
+    auto& chainstate = node.chainman->ActiveChainstate();
+
+    MockTime(fuzzed_data_provider, chainstate);
+    SetMempoolConstraints(*node.args, fuzzed_data_provider);
 
     std::vector<uint256> txids;
     for (const auto& outpoint : g_outpoints_coinbase_init_mature) {
@@ -265,11 +277,29 @@ FUZZ_TARGET_INIT(tx_pool, initialize_tx_pool)
         txids.push_back(ConsumeUInt256(fuzzed_data_provider));
     }
 
-    CTxMemPool tx_pool{/* estimator */ nullptr, /* check_ratio */ 1};
+    CTxMemPool tx_pool_{/* estimator */ nullptr, /* check_ratio */ 1};
+    MockedTxPool& tx_pool = *static_cast<MockedTxPool*>(&tx_pool_);
 
     while (fuzzed_data_provider.ConsumeBool()) {
         const auto mut_tx = ConsumeTransaction(fuzzed_data_provider, txids);
 
+        if (fuzzed_data_provider.ConsumeBool()) {
+            MockTime(fuzzed_data_provider, chainstate);
+        }
+        if (fuzzed_data_provider.ConsumeBool()) {
+            SetMempoolConstraints(*node.args, fuzzed_data_provider);
+        }
+        if (fuzzed_data_provider.ConsumeBool()) {
+            tx_pool.RollingFeeUpdate();
+        }
+        if (fuzzed_data_provider.ConsumeBool()) {
+            const auto& txid = fuzzed_data_provider.ConsumeBool() ?
+                                   mut_tx.GetHash() :
+                                   PickValue(fuzzed_data_provider, txids);
+            const auto delta = fuzzed_data_provider.ConsumeIntegralInRange<CAmount>(-50 * COIN, +50 * COIN);
+            tx_pool.PrioritiseTransaction(txid, delta);
+        }
+
         const auto tx = MakeTransactionRef(mut_tx);
         const bool bypass_limits = fuzzed_data_provider.ConsumeBool();
         ::fRequireStandard = fuzzed_data_provider.ConsumeBool();