test: add test for CChainState::ResizeCoinsCaches()

src/Makefile.test.include

@@ -256,6 +256,7 @@ BITCOIN_TESTS =\
   test/uint256_tests.cpp \
   test/util_tests.cpp \
   test/validation_block_tests.cpp \
+  test/validation_chainstate_tests.cpp \
   test/validation_chainstatemanager_tests.cpp \
   test/validation_flush_tests.cpp \
   test/validationinterface_tests.cpp \

src/test/validation_chainstate_tests.cpp

@@ -0,0 +1,76 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+//
+#include <random.h>
+#include <uint256.h>
+#include <consensus/validation.h>
+#include <sync.h>
+#include <test/util/setup_common.h>
+#include <validation.h>
+
+#include <vector>
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(validation_chainstate_tests, TestingSetup)
+
+//! Test resizing coins-related CChainState caches during runtime.
+//!
+BOOST_AUTO_TEST_CASE(validation_chainstate_resize_caches)
+{
+    ChainstateManager manager;
+
+    //! Create and add a Coin with DynamicMemoryUsage of 80 bytes to the given view.
+    auto add_coin = [](CCoinsViewCache& coins_view) -> COutPoint {
+        Coin newcoin;
+        uint256 txid = InsecureRand256();
+        COutPoint outp{txid, 0};
+        newcoin.nHeight = 1;
+        newcoin.out.nValue = InsecureRand32();
+        newcoin.out.scriptPubKey.assign((uint32_t)56, 1);
+        coins_view.AddCoin(outp, std::move(newcoin), false);
+
+        return outp;
+    };
+
+    ENTER_CRITICAL_SECTION(cs_main);
+    CChainState& c1 = manager.InitializeChainstate();
+    LEAVE_CRITICAL_SECTION(cs_main);
+    c1.InitCoinsDB(
+        /* cache_size_bytes */ 1 << 23, /* in_memory */ true, /* should_wipe */ false);
+    WITH_LOCK(::cs_main, c1.InitCoinsCache(1 << 23));
+
+    // Add a coin to the in-memory cache, upsize once, then downsize.
+    {
+        LOCK(::cs_main);
+        auto outpoint = add_coin(c1.CoinsTip());
+
+        // Set a meaningless bestblock value in the coinsview cache - otherwise we won't
+        // flush during ResizecoinsCaches() and will subsequently hit an assertion.
+        c1.CoinsTip().SetBestBlock(InsecureRand256());
+
+        BOOST_CHECK(c1.CoinsTip().HaveCoinInCache(outpoint));
+
+        c1.ResizeCoinsCaches(
+            1 << 24,  // upsizing the coinsview cache
+            1 << 22  // downsizing the coinsdb cache
+        );
+
+        // View should still have the coin cached, since we haven't destructed the cache on upsize.
+        BOOST_CHECK(c1.CoinsTip().HaveCoinInCache(outpoint));
+
+        c1.ResizeCoinsCaches(
+            1 << 22,  // downsizing the coinsview cache
+            1 << 23  // upsizing the coinsdb cache
+        );
+
+        // The view cache should be empty since we had to destruct to downsize.
+        BOOST_CHECK(!c1.CoinsTip().HaveCoinInCache(outpoint));
+    }
+
+    // Avoid triggering the address sanitizer.
+    WITH_LOCK(::cs_main, manager.Unload());
+}
+
+BOOST_AUTO_TEST_SUITE_END()