diff --git a/atdna/test.cpp b/atdna/test.cpp
index f23c929..ede95de 100644
--- a/atdna/test.cpp
+++ b/atdna/test.cpp
@@ -1,5 +1,7 @@
 #include "test.hpp"
-#include "athena/MemoryWriter.hpp"
+
+#include <athena/MemoryWriter.hpp>
+#include <fmt/format.h>
 
 #define EXPECTED_BYTES 281
 
@@ -13,11 +15,14 @@ int main(int argc, const char** argv) {
   athena::io::MemoryCopyWriter w(nullptr, binSize);
   atInt64 pos = w.position();
   file.write(w);
-  bool pass = !w.hasError() && w.position() - pos == binSize && binSize == EXPECTED_BYTES;
-  if (pass)
-    printf("[PASS] %" PRISize " bytes written\n", size_t(w.position() - pos));
-  else
-    printf("[FAIL] %" PRISize " bytes written; %" PRISize " bytes sized; %d bytes expected\n",
-           size_t(w.position() - pos), binSize, EXPECTED_BYTES);
+
+  const bool pass = !w.hasError() && w.position() - pos == binSize && binSize == EXPECTED_BYTES;
+  if (pass) {
+    fmt::print(fmt("[PASS] {} bytes written\n"), size_t(w.position() - pos));
+  } else {
+    fmt::print(fmt("[FAIL] {} bytes written; {} bytes sized; {} bytes expected\n"), size_t(w.position() - pos), binSize,
+               EXPECTED_BYTES);
+  }
+
   return pass ? 0 : 1;
 }