--- /dev/null
+++ libmalloc/libmalloc-283/tests/introspect_tests.c
@@ -0,0 +1,88 @@
+//
+//  introspect_tests.c
+//  libmalloc
+//
+//  Tests malloc introspection features
+//
+
+#include <TargetConditionals.h>
+#include <darwintest.h>
+#include <darwintest_utils.h>
+#include <spawn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <malloc/malloc.h>
+#include <../private/malloc_private.h>
+#include <../src/internal.h>
+
+extern malloc_zone_t **malloc_zones;
+
+void check_stats(malloc_zone_t *zone, malloc_statistics_t *stats) 
+{
+	malloc_statistics_t stats2 = {};
+	zone->introspect->statistics(zone, &stats2);
+	T_QUIET; T_EXPECT_EQ(stats->blocks_in_use, stats2.blocks_in_use, "blocks_in_use matches");
+	T_QUIET; T_EXPECT_EQ(stats->size_in_use, stats2.size_in_use, "size_in_use matches");	
+	T_QUIET; T_EXPECT_EQ(stats->blocks_in_use, stats2.blocks_in_use, "blocks_in_use matches");
+	T_QUIET; T_EXPECT_EQ(stats->size_allocated, stats2.size_allocated, "size_allocated matches");
+}
+
+
+void test_stats(int limit) 
+{
+	malloc_statistics_t stats = {};
+	malloc_statistics_t old_stats = {};
+
+	malloc_zone_t *zone = malloc_zones[0];
+
+	T_ASSERT_GE(zone->version, 12, "zone version is at least 12");
+
+	zone->introspect->task_statistics(mach_task_self(), (vm_address_t)zone, NULL, &old_stats);
+	check_stats(zone, &old_stats);
+
+	T_LOG("testing statistics for allocations from 1 to %d", limit);
+	
+	for (int i = 0; i < limit; i++) {
+		void *ptr = malloc(i);
+		T_QUIET; T_ASSERT_NOTNULL(ptr, "ptr isn't null");
+		size_t size = malloc_size(ptr);
+		zone->introspect->task_statistics(mach_task_self(), (vm_address_t)zone, NULL, &stats);
+		check_stats(zone, &stats);
+		if (stats.blocks_in_use == old_stats.blocks_in_use) {
+			T_LOG("last-free cache hit at size %d", i);
+			/* It's possible we hit the last-free cache.   Try one more allocation. */
+			ptr = malloc(i);
+			T_QUIET; T_ASSERT_NOTNULL(ptr, "ptr isn't null");
+			size = malloc_size(ptr);
+			zone->introspect->task_statistics(mach_task_self(), (vm_address_t)zone, NULL, &stats);
+			check_stats(zone, &stats);
+		}
+		T_QUIET; T_EXPECT_EQ(stats.size_in_use, old_stats.size_in_use+size, "%ld more bytes in use", (long)size);
+		T_QUIET; T_EXPECT_EQ(stats.blocks_in_use, old_stats.blocks_in_use+1, "one more block in use");
+		old_stats = stats;
+	}
+	
+	T_LOG("done");
+}
+
+T_DECL(nano_statistics_test, "Test that we can introspect nano zone statistics",
+	   T_META_ENVVAR("MallocNanoZone=V2"), T_META_CHECK_LEAKS(false))
+{
+#if CONFIG_NANOZONE
+	(void)malloc(16);
+	T_ASSERT_EQ(malloc_engaged_nano(), 2, "Nanozone v2 engaged");
+	test_stats(256);
+#else // CONFIG_NANOZONE
+	T_SKIP("Nano allocator not configured");
+#endif // CONFIG_NANOZONE
+}
+
+
+T_DECL(szone_statistics_test, "Test that we can introspect szone zone statistics",
+	   T_META_ENVVAR("MallocNanoZone=0"), T_META_CHECK_LEAKS(false))
+{
+	(void)malloc(16);
+	T_ASSERT_EQ(malloc_engaged_nano(), 0, "Nanozone not engaged");
+	test_stats(5000);
+}