1 files changed, 36 insertions, 3 deletions

diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index e082800fc3..853dc6dc1e 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -6,6 +6,7 @@
 #include <coins.h>
 #include <script/standard.h>
 #include <streams.h>
+#include <test/util/poolresourcetester.h>
 #include <test/util/random.h>
 #include <test/util/setup_common.h>
 #include <txdb.h>
@@ -612,7 +613,8 @@ void GetCoinsMapEntry(const CCoinsMap& map, CAmount& value, char& flags, const C
 
 void WriteCoinsViewEntry(CCoinsView& view, CAmount value, char flags)
 {
-    CCoinsMap map;
+    CCoinsMapMemoryResource resource;
+    CCoinsMap map{0, CCoinsMap::hasher{}, CCoinsMap::key_equal{}, &resource};
     InsertCoinsMapEntry(map, value, flags);
     BOOST_CHECK(view.BatchWrite(map, {}));
 }
@@ -911,6 +913,7 @@ void TestFlushBehavior(
     CAmount value;
     char flags;
     size_t cache_usage;
+    size_t cache_size;
 
     auto flush_all = [&all_caches](bool erase) {
         // Flush in reverse order to ensure that flushes happen from children up.
@@ -935,6 +938,8 @@ void TestFlushBehavior(
     view->AddCoin(outp, Coin(coin), false);
 
     cache_usage = view->DynamicMemoryUsage();
+    cache_size = view->map().size();
+
     // `base` shouldn't have coin (no flush yet) but `view` should have cached it.
     BOOST_CHECK(!base.HaveCoin(outp));
     BOOST_CHECK(view->HaveCoin(outp));
@@ -949,6 +954,7 @@ void TestFlushBehavior(
 
     // CoinsMap usage should be unchanged since we didn't erase anything.
     BOOST_CHECK_EQUAL(cache_usage, view->DynamicMemoryUsage());
+    BOOST_CHECK_EQUAL(cache_size, view->map().size());
 
     // --- 3. Ensuring the entry still exists in the cache and has been written to parent
     //
@@ -965,8 +971,10 @@ void TestFlushBehavior(
         //
         flush_all(/*erase=*/ true);
 
-        // Memory usage should have gone down.
-        BOOST_CHECK(view->DynamicMemoryUsage() < cache_usage);
+        // Memory does not necessarily go down due to the map using a memory pool
+        BOOST_TEST(view->DynamicMemoryUsage() <= cache_usage);
+        // Size of the cache must go down though
+        BOOST_TEST(view->map().size() < cache_size);
 
         // --- 5. Ensuring the entry is no longer in the cache
         //
@@ -1076,4 +1084,29 @@ BOOST_AUTO_TEST_CASE(ccoins_flush_behavior)
     }
 }
 
+BOOST_AUTO_TEST_CASE(coins_resource_is_used)
+{
+    CCoinsMapMemoryResource resource;
+    PoolResourceTester::CheckAllDataAccountedFor(resource);
+
+    {
+        CCoinsMap map{0, CCoinsMap::hasher{}, CCoinsMap::key_equal{}, &resource};
+        BOOST_TEST(memusage::DynamicUsage(map) >= resource.ChunkSizeBytes());
+
+        map.reserve(1000);
+
+        // The resource has preallocated a chunk, so we should have space for at several nodes without the need to allocate anything else.
+        const auto usage_before = memusage::DynamicUsage(map);
+
+        COutPoint out_point{};
+        for (size_t i = 0; i < 1000; ++i) {
+            out_point.n = i;
+            map[out_point];
+        }
+        BOOST_TEST(usage_before == memusage::DynamicUsage(map));
+    }
+
+    PoolResourceTester::CheckAllDataAccountedFor(resource);
+}
+
 BOOST_AUTO_TEST_SUITE_END()