diff --git a/include/xo/object2/DString.hpp b/include/xo/object2/DString.hpp
index bf8f04f..a029da3 100644
--- a/include/xo/object2/DString.hpp
+++ b/include/xo/object2/DString.hpp
@@ -87,10 +87,10 @@ namespace xo {
              *  @return pointer to newly created DString
              **/
             template <typename... Args>
-            static DString * snprintf(obj<AAllocator> mm,
-                                      size_type cap,
-                                      const char * fmt,
-                                      Args&&... args)
+            static DString * printf(obj<AAllocator> mm,
+                                    size_type cap,
+                                    const char * fmt,
+                                    Args&&... args)
             {
                 DString * result = DString::empty(mm, cap);
                 if (result) {
@@ -148,7 +148,12 @@ namespace xo {
              **/
             template <typename... Args>
             size_type sprintf(const char * fmt, Args&&... args) {
-                int n = std::snprintf(chars_, capacity_, fmt, std::forward<Args>(args)...);
+                int n;
+                if constexpr (sizeof...(Args) == 0) {
+                    n = std::snprintf(chars_, capacity_, "%s", fmt);
+                } else {
+                    n = std::snprintf(chars_, capacity_, fmt, std::forward<Args>(args)...);
+                }
                 if (n < 0) {
                     size_ = 0;
                     chars_[0] = '\0';
diff --git a/utest/Printable.test.cpp b/utest/Printable.test.cpp
index c1b63dc..f61e06a 100644
--- a/utest/Printable.test.cpp
+++ b/utest/Printable.test.cpp
@@ -12,6 +12,10 @@
 #include <xo/object2/IGCObject_DList.hpp>
 #include <xo/object2/IPrintable_DList.hpp>
 
+#include <xo/object2/DString.hpp>
+#include <xo/object2/string/IGCObject_DString.hpp>
+#include <xo/object2/string/IPrintable_DString.hpp>
+
 #include <xo/object2/DInteger.hpp>
 #include <xo/object2/IGCObject_DInteger.hpp>
 
@@ -35,6 +39,7 @@ namespace ut {
     using xo::scm::ListOps;
     using xo::scm::DList;
     using xo::scm::DInteger;
+    using xo::scm::DString;
     using xo::mm::AAllocator;
     using xo::mm::ACollector;
     using xo::mm::AGCObject;
@@ -70,10 +75,10 @@ namespace ut {
         std::vector<testcase_pp>
         s_testcase_v = {
             testcase_pp(16384, 8192, 0, "()"),
-            testcase_pp(16384, 8192, 1, "(1000)"),
-            testcase_pp(16384, 8192, 2, "(1000 1197)"),
-            testcase_pp(16384, 8192, 5, "(1000 1197 1394 1591 1788)"),
-            testcase_pp(16384, 8192, 10, "(1000 1197 1394 1591 1788 1985 2182 2379 2576 2773)"),
+            testcase_pp(16384, 8192, 1, "(01000)"),
+            testcase_pp(16384, 8192, 2, "(01000 1197)"),
+            testcase_pp(16384, 8192, 5, "(01000 1197 01394 1591 01788)"),
+            testcase_pp(16384, 8192, 10, "(01000 1197 01394 1591 01788 1985 02182 2379 02576 2773)"),
             testcase_pp(16384, 8192, 20, "(...)"),
         };
     }
@@ -117,9 +122,17 @@ namespace ut {
                 c_o.add_gc_root(&l0_o);
 
                 for(int ip1 = tc.list_.size(); ip1 > 0; --ip1) {
-                    auto xi_o = DInteger::box<AGCObject>(gc_o, tc.list_[ip1 - 1]);
+                    obj<AGCObject> elt;
 
-                    l0_o  = ListOps::cons(gc_o, xi_o, l0_o);
+                    //elt = DInteger::box<AGCObject>(gc_o, tc.list_[ip1 - 1]);
+
+                    if (ip1 % 2 == 0) {
+                        elt = DInteger::box<AGCObject>(gc_o, tc.list_[ip1 - 1]);
+                    } else {
+                        elt = obj<AGCObject,DString>(DString::printf(gc_o, 80, "%05d", tc.list_[ip1 - 1]));
+                    }
+
+                    l0_o  = ListOps::cons(gc_o, elt, l0_o);
                 }
 
                 // TODO: log_streambuf using DArena