test: Add arguments for creating a slimmer setup

Adds more testing options for creating an environment without networking
and a validation interface. This is useful for improving the performance
of the utxo snapshot fuzz test, which constructs a new TestingSetup on
each iteration.

src/test/fuzz/utxo_snapshot.cpp

@@ -31,7 +31,13 @@ void initialize_chain()
 FUZZ_TARGET(utxo_snapshot, .init = initialize_chain)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    std::unique_ptr<const TestingSetup> setup{MakeNoLogFileContext<const TestingSetup>()};
+    std::unique_ptr<const TestingSetup> setup{
+        MakeNoLogFileContext<const TestingSetup>(
+            ChainType::REGTEST,
+            TestOpts{
+                .setup_net = false,
+                .setup_validation_interface = false,
+            })};
     const auto& node = setup->m_node;
     auto& chainman{*node.chainman};
 

src/test/util/setup_common.cpp

@@ -218,9 +218,11 @@ ChainTestingSetup::ChainTestingSetup(const ChainType chainType, TestOpts opts)
 
     // We have to run a scheduler thread to prevent ActivateBestChain
     // from blocking due to queue overrun.
-    m_node.scheduler = std::make_unique<CScheduler>();
+    if (opts.setup_validation_interface) {
-    m_node.scheduler->m_service_thread = std::thread(util::TraceThread, "scheduler", [&] { m_node.scheduler->serviceQueue(); });
+        m_node.scheduler = std::make_unique<CScheduler>();
-    m_node.validation_signals = std::make_unique<ValidationSignals>(std::make_unique<SerialTaskRunner>(*m_node.scheduler));
+        m_node.scheduler->m_service_thread = std::thread(util::TraceThread, "scheduler", [&] { m_node.scheduler->serviceQueue(); });
+        m_node.validation_signals = std::make_unique<ValidationSignals>(std::make_unique<SerialTaskRunner>(*m_node.scheduler));
+    }
 
     m_node.fee_estimator = std::make_unique<CBlockPolicyEstimator>(FeeestPath(*m_node.args), DEFAULT_ACCEPT_STALE_FEE_ESTIMATES);
     bilingual_str error{};
@@ -255,7 +257,7 @@ ChainTestingSetup::ChainTestingSetup(const ChainType chainType, TestOpts opts)
 ChainTestingSetup::~ChainTestingSetup()
 {
     if (m_node.scheduler) m_node.scheduler->stop();
-    m_node.validation_signals->FlushBackgroundCallbacks();
+    if (m_node.validation_signals) m_node.validation_signals->FlushBackgroundCallbacks();
     m_node.connman.reset();
     m_node.banman.reset();
     m_node.addrman.reset();
@@ -306,6 +308,8 @@ TestingSetup::TestingSetup(
 
     LoadVerifyActivateChainstate();
 
+    if (!opts.setup_net) return;
+
     m_node.netgroupman = std::make_unique<NetGroupManager>(/*asmap=*/std::vector<bool>());
     m_node.addrman = std::make_unique<AddrMan>(*m_node.netgroupman,
                                                /*deterministic=*/false,

src/test/util/setup_common.h

@@ -52,6 +52,8 @@ struct TestOpts {
     std::vector<const char*> extra_args{};
     bool coins_db_in_memory{true};
     bool block_tree_db_in_memory{true};
+    bool setup_net{true};
+    bool setup_validation_interface{true};
 };
 
 /** Basic testing setup.