diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb
index ccb46aeb9bd29b..a12b076e53f880 100644
--- a/test/ruby/test_gc.rb
+++ b/test/ruby/test_gc.rb
@@ -701,7 +701,9 @@ def allocate_large_object = Array.new(10)
         allocate_large_object
       end
 
-      assert_operator(GC.stat(:heap_available_slots), :<, COUNT * 2)
+      heap_available_slots = GC.stat(:heap_available_slots)
+
+      assert_operator(heap_available_slots, :<, COUNT * 2, "GC.stat: #{GC.stat}\nGC.stat_heap: #{GC.stat_heap}")
     RUBY
   end