diff --git a/utest/IAlloc.test.cpp b/utest/IAlloc.test.cpp
new file mode 100644
index 00000000..b0214749
--- /dev/null
+++ b/utest/IAlloc.test.cpp
@@ -0,0 +1,29 @@
+/* @file IAlloc.test.cpp
+ *
+ * author: Roland Conybeare, Aug 2025
+ */
+
+#include "xo/alloc/IAlloc.hpp"
+#include <catch2/catch.hpp>
+
+namespace xo {
+    using xo::gc::IAlloc;
+
+    namespace ut {
+        TEST_CASE("ialloc", "[alloc]")
+        {
+            REQUIRE(IAlloc::alloc_padding(0) == 0);
+            REQUIRE(IAlloc::alloc_padding(1) == 7);
+            REQUIRE(IAlloc::alloc_padding(2) == 6);
+            REQUIRE(IAlloc::alloc_padding(3) == 5);
+            REQUIRE(IAlloc::alloc_padding(4) == 4);
+            REQUIRE(IAlloc::alloc_padding(5) == 3);
+            REQUIRE(IAlloc::alloc_padding(6) == 2);
+            REQUIRE(IAlloc::alloc_padding(7) == 1);
+            REQUIRE(IAlloc::alloc_padding(8) == 0);
+            REQUIRE(IAlloc::alloc_padding(9) == 7);
+        }
+    } /*namespace ut*/
+} /*namespace xo*/
+
+/* end IAlloc.test.cpp */