test/fuzz: Invoke LoadMempool via CChainState

Not only does this increase coverage, it is also more correct in that
when ::LoadMempool is called with a mempool and chainstate, it calls
AcceptToMemoryPool with just the chainstate.

AcceptToMemoryPool will then act on the chainstate's mempool via
CChainState::GetMempool, which may be different from the mempool
originally passed to ::LoadMempool. (In this fuzz test's case, it
definitely is different)

Also, move DummyChainstate to its own file since it's now used by the
validation_load_mempool fuzz test to replace CChainState's m_mempool.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index b757fed055..f5a678bf85 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3865,11 +3865,11 @@ void PruneBlockFilesManual(CChainState& active_chainstate, int nManualPruneHeigh
     }
 }
 
-void CChainState::LoadMempool(const ArgsManager& args)
+void CChainState::LoadMempool(const ArgsManager& args, FopenFn mockable_fopen_function)
 {
     if (!m_mempool) return;
     if (args.GetBoolArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) {
-        ::LoadMempool(*m_mempool, *this);
+        ::LoadMempool(*m_mempool, *this, mockable_fopen_function);
     }
     m_mempool->SetLoadTried(!ShutdownRequested());
 }