2 files changed, 21 insertions, 2 deletions
diff --git a/tests/timestamp/buildfile b/tests/timestamp/buildfile
index 085daf0..c554fc3 100644
--- a/tests/timestamp/buildfile
+++ b/tests/timestamp/buildfile
@@ -4,4 +4,10 @@
 
 import libs = libbutl%lib{butl}
 
+if ($cxx.features.modules && ($force_std_modules == true || $cxx.id != 'msvc'))
+{
+  import libs += libstd-modules%liba{std-modules}
+  cxx.poptions += -D__cpp_lib_modules
+}
+
 exe{driver}: {hxx cxx}{*} $libs
diff --git a/tests/timestamp/driver.cxx b/tests/timestamp/driver.cxx
index 661deb2..ec4c49d 100644
--- a/tests/timestamp/driver.cxx
+++ b/tests/timestamp/driver.cxx
@@ -4,15 +4,28 @@
 
 #include <time.h> // tzset() (POSIX), _tzset() (Windows)
 
+#include <cassert>
+
+#ifndef __cpp_lib_modules
 #include <chrono>
 #include <locale>
 #include <clocale>
-#include <cassert>
 #include <sstream>
 #include <iomanip>
 #include <system_error>
+#endif
 
-#include <libbutl/timestamp.hxx>
+// Other includes.
+
+#ifdef __cpp_modules
+#ifdef __cpp_lib_modules
+import std.core;
+import std.io;
+#endif
+import butl.timestamp;
+#else
+#include <libbutl/timestamp.mxx>
+#endif
 
 using namespace std;
 using namespace butl;