diff --git a/rostests/kmtests/rtl/RtlSplayTree.c b/rostests/kmtests/rtl/RtlSplayTree.c
index 1e4b739b4d2..db0e32a6276 100644
--- a/rostests/kmtests/rtl/RtlSplayTree.c
+++ b/rostests/kmtests/rtl/RtlSplayTree.c
@@ -60,7 +60,9 @@ static void RtlSplayTreeTest()
              sizeof(Text[i]),
              &WasNew);
         ok(Ch && *Ch == Text[i], "Copy character into node\n");
-        ok(WasNew == (NewE[i] == '1'), "Character newness didn't match\n");
+        ok(WasNew == (NewE[i] == '1'),
+           "Character newness didn't match for char %u: '%c'\n",
+           i, Text[i]);
     }
     for (Ch = (PCHAR)RtlEnumerateGenericTable(&Table, TRUE), i = 0;
          Ch;