--- /dev/null
+++ libmalloc/libmalloc-792.41.1/tests/realloc.c
@@ -0,0 +1,38 @@
+#include <darwintest.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+#include <malloc/malloc.h>
+
+T_DECL(realloc_failure, "realloc failure", T_META_TAG_ALL_ALLOCATORS,
+		T_META_TAG("no_debug"), T_META_TAG_VM_PREFERRED)
+{
+	void *a = malloc(16);
+	T_ASSERT_NOTNULL(a, "malloc(16)");
+	void *b = realloc(a, SIZE_MAX - (1 << 17));
+	errno_t error = errno;
+	size_t a_sz = malloc_size(a);
+
+	T_ASSERT_NULL(b, "realloc should fail");
+	T_ASSERT_EQ(error, ENOMEM, "failure should have been ENOMEM");
+
+	T_ASSERT_GT(a_sz, 0ul, "The original pointer should not have been freed");
+
+	free(a);
+}
+
+T_DECL(reallocf_failure, "reallocf failure", T_META_TAG_ALL_ALLOCATORS,
+		T_META_TAG("no_debug"), T_META_TAG_VM_PREFERRED)
+{
+	// rdar://134443969: Avoid the tiny zone because it may madvise
+	void *a = malloc(65536);
+	T_ASSERT_NOTNULL(a, "malloc(65536)");
+	void *b = reallocf(a, SIZE_MAX - (1 << 17));
+	errno_t error = errno;
+	size_t a_sz = malloc_size(a);
+
+	T_ASSERT_NULL(b, "reallocf should fail");
+	T_ASSERT_EQ(error, ENOMEM, "failure should have been ENOMEM");
+
+	T_ASSERT_EQ(a_sz, 0ul, "The original pointer should have been freed");
+}