Give CMainSignals a reference to the global scheduler

...so that it can run some signals in the background later

src/test/test_bitcoin.cpp

@@ -62,6 +62,12 @@ TestingSetup::TestingSetup(const std::string& chainName) : BasicTestingSetup(cha
         pathTemp = GetTempPath() / strprintf("test_bitcoin_%lu_%i", (unsigned long)GetTime(), (int)(InsecureRandRange(100000)));
         fs::create_directories(pathTemp);
         ForceSetArg("-datadir", pathTemp.string());
+
+        // Note that because we don't bother running a scheduler thread here,
+        // callbacks via CValidationInterface are unreliable, but that's OK,
+        // our unit tests aren't testing multiple parts of the code at once.
+        GetMainSignals().RegisterBackgroundSignalScheduler(scheduler);
+
         mempool.setSanityCheck(1.0);
         pblocktree = new CBlockTreeDB(1 << 20, true);
         pcoinsdbview = new CCoinsViewDB(1 << 23, true);
@@ -88,6 +94,7 @@ TestingSetup::~TestingSetup()
         UnregisterNodeSignals(GetNodeSignals());
         threadGroup.interrupt_all();
         threadGroup.join_all();
+        GetMainSignals().UnregisterBackgroundSignalScheduler();
         UnloadBlockIndex();
         delete pcoinsTip;
         delete pcoinsdbview;

src/test/test_bitcoin.h

@@ -10,6 +10,7 @@
 #include "key.h"
 #include "pubkey.h"
 #include "random.h"
+#include "scheduler.h"
 #include "txdb.h"
 #include "txmempool.h"
 
@@ -53,6 +54,7 @@ struct TestingSetup: public BasicTestingSetup {
     fs::path pathTemp;
     boost::thread_group threadGroup;
     CConnman* connman;
+    CScheduler scheduler;
 
     TestingSetup(const std::string& chainName = CBaseChainParams::MAIN);
     ~TestingSetup();