scripted-diff: test: Use CTxMemPool in TestingSetup

After this commit, there should be no explicit instantiation of
CTxMemPool in src/test other than those in fuzz/ and setup_common

-BEGIN VERIFY SCRIPT-
find_regex="CTxMemPool\s+([^;({]+)(|\(\)|\{\});" \
    && git grep -l -E "$find_regex" -- src/test \
        | grep -v -e "^src/test/util/setup_common.cpp$" \
                  -e "^src/test/fuzz/" \
        | xargs sed -i -E "s@$find_regex@CTxMemPool\& \1 = *Assert(m_node.mempool);@g"
-END VERIFY SCRIPT-

src/test/blockencodings_tests.cpp

@@ -54,7 +54,7 @@ constexpr long SHARED_TX_OFFSET{3};
 
 BOOST_AUTO_TEST_CASE(SimpleRoundTripTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     TestMemPoolEntryHelper entry;
     CBlock block(BuildBlockTestCase());
 
@@ -137,7 +137,7 @@ public:
 
 BOOST_AUTO_TEST_CASE(NonCoinbasePreforwardRTTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     TestMemPoolEntryHelper entry;
     CBlock block(BuildBlockTestCase());
 
@@ -207,7 +207,7 @@ BOOST_AUTO_TEST_CASE(NonCoinbasePreforwardRTTest)
 
 BOOST_AUTO_TEST_CASE(SufficientPreforwardRTTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     TestMemPoolEntryHelper entry;
     CBlock block(BuildBlockTestCase());
 
@@ -258,7 +258,7 @@ BOOST_AUTO_TEST_CASE(SufficientPreforwardRTTest)
 
 BOOST_AUTO_TEST_CASE(EmptyBlockRoundTripTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     CMutableTransaction coinbase;
     coinbase.vin.resize(1);
     coinbase.vin[0].scriptSig.resize(10);

src/test/mempool_tests.cpp

@@ -56,7 +56,7 @@ BOOST_AUTO_TEST_CASE(MempoolRemoveTest)
     }
 
 
-    CTxMemPool testPool;
+    CTxMemPool& testPool = *Assert(m_node.mempool);
     LOCK2(cs_main, testPool.cs);
 
     // Nothing in pool, remove should do nothing:
@@ -121,7 +121,7 @@ static void CheckSort(CTxMemPool& pool, std::vector<std::string>& sortedOrder) E
 
 BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     LOCK2(cs_main, pool.cs);
     TestMemPoolEntryHelper entry;
 
@@ -294,7 +294,7 @@ BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
 
 BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     LOCK2(cs_main, pool.cs);
     TestMemPoolEntryHelper entry;
 
@@ -423,7 +423,7 @@ BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
 
 BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
 {
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     LOCK2(cs_main, pool.cs);
     TestMemPoolEntryHelper entry;
 
@@ -594,7 +594,7 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTests)
 {
     size_t ancestors, descendants;
 
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     LOCK2(cs_main, pool.cs);
     TestMemPoolEntryHelper entry;
 
@@ -753,7 +753,7 @@ BOOST_AUTO_TEST_CASE(MempoolAncestryTestsDiamond)
 {
     size_t ancestors, descendants;
 
-    CTxMemPool pool;
+    CTxMemPool& pool = *Assert(m_node.mempool);
     LOCK2(::cs_main, pool.cs);
     TestMemPoolEntryHelper entry;
 

src/test/validation_chainstate_tests.cpp

@@ -30,7 +30,7 @@ BOOST_AUTO_TEST_CASE(validation_chainstate_resize_caches)
     ChainstateManager manager{chainman_opts};
 
     WITH_LOCK(::cs_main, manager.m_blockman.m_block_tree_db = std::make_unique<CBlockTreeDB>(1 << 20, true));
-    CTxMemPool mempool;
+    CTxMemPool& mempool = *Assert(m_node.mempool);
 
     //! Create and add a Coin with DynamicMemoryUsage of 80 bytes to the given view.
     auto add_coin = [](CCoinsViewCache& coins_view) -> COutPoint {

src/test/validation_flush_tests.cpp

@@ -20,7 +20,7 @@ BOOST_FIXTURE_TEST_SUITE(validation_flush_tests, ChainTestingSetup)
 //!
 BOOST_AUTO_TEST_CASE(getcoinscachesizestate)
 {
-    CTxMemPool mempool;
+    CTxMemPool& mempool = *Assert(m_node.mempool);
     BlockManager blockman{};
     CChainState chainstate{&mempool, blockman, *Assert(m_node.chainman)};
     chainstate.InitCoinsDB(/*cache_size_bytes=*/1 << 10, /*in_memory=*/true, /*should_wipe=*/false);