test: Avoid resetting mocktime in testing setup

This allows to set the mocktime before the testing setup.

Also, in some fuzz tests the mocktime was reset to 0 before this change,
so set it.

src/init.cpp

@@ -1052,7 +1052,9 @@ bool AppInitParameterInteraction(const ArgsManager& args)
     if (!g_wallet_init_interface.ParameterInteraction()) return false;
 
     // Option to startup with mocktime set (used for regression testing):
-    SetMockTime(args.GetIntArg("-mocktime", 0)); // SetMockTime(0) is a no-op
+    if (const auto mocktime{args.GetIntArg("-mocktime")}) {
+        SetMockTime(std::chrono::seconds{*mocktime});
+    }
 
     if (args.GetBoolArg("-peerbloomfilters", DEFAULT_PEERBLOOMFILTERS))
         g_local_services = ServiceFlags(g_local_services | NODE_BLOOM);

src/test/fuzz/package_eval.cpp

@@ -42,6 +42,7 @@ void initialize_tx_pool()
 {
     static const auto testing_setup = MakeNoLogFileContext<const TestingSetup>();
     g_setup = testing_setup.get();
+    SetMockTime(WITH_LOCK(g_setup->m_node.chainman->GetMutex(), return g_setup->m_node.chainman->ActiveTip()->Time()));
 
     BlockAssembler::Options options;
     options.coinbase_output_script = P2WSH_EMPTY;

src/test/fuzz/process_message.cpp

@@ -44,6 +44,7 @@ void initialize_process_message()
             /*chain_type=*/ChainType::REGTEST,
             {.extra_args = {"-txreconciliation"}});
     g_setup = testing_setup.get();
+    SetMockTime(WITH_LOCK(g_setup->m_node.chainman->GetMutex(), return g_setup->m_node.chainman->ActiveTip()->Time()));
     for (int i = 0; i < 2 * COINBASE_MATURITY; i++) {
         MineBlock(g_setup->m_node, {});
     }

src/test/fuzz/process_messages.cpp

@@ -34,6 +34,7 @@ void initialize_process_messages()
             /*chain_type=*/ChainType::REGTEST,
             {.extra_args = {"-txreconciliation"}});
     g_setup = testing_setup.get();
+    SetMockTime(WITH_LOCK(g_setup->m_node.chainman->GetMutex(), return g_setup->m_node.chainman->ActiveTip()->Time()));
     for (int i = 0; i < 2 * COINBASE_MATURITY; i++) {
         MineBlock(g_setup->m_node, {});
     }

src/test/fuzz/tx_pool.cpp

@@ -44,6 +44,7 @@ void initialize_tx_pool()
 {
     static const auto testing_setup = MakeNoLogFileContext<const TestingSetup>();
     g_setup = testing_setup.get();
+    SetMockTime(WITH_LOCK(g_setup->m_node.chainman->GetMutex(), return g_setup->m_node.chainman->ActiveTip()->Time()));
 
     BlockAssembler::Options options;
     options.coinbase_output_script = P2WSH_OP_TRUE;

src/test/fuzz/utxo_snapshot.cpp

@@ -72,6 +72,7 @@ void initialize_chain()
     const auto params{CreateChainParams(ArgsManager{}, ChainType::REGTEST)};
     static const auto chain{CreateBlockChain(2 * COINBASE_MATURITY, *params)};
     g_chain = &chain;
+    SetMockTime(chain.back()->Time());
 
     // Make sure we can generate a valid snapshot.
     sanity_check_snapshot();

src/test/fuzz/utxo_total_supply.cpp

@@ -24,14 +24,13 @@ FUZZ_TARGET(utxo_total_supply)
 {
     SeedRandomStateForTest(SeedRand::ZEROS);
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    const auto mock_time{ConsumeTime(fuzzed_data_provider, /*min=*/1296688602)}; // regtest genesis block timestamp
+    SetMockTime(ConsumeTime(fuzzed_data_provider, /*min=*/1296688602)); // regtest genesis block timestamp
     /** The testing setup that creates a chainman only (no chainstate) */
     ChainTestingSetup test_setup{
         ChainType::REGTEST,
         {
             .extra_args = {
                 "-testactivationheight=bip34@2",
-                strprintf("-mocktime=%d", mock_time).c_str()
             },
         },
     };