2 files changed, 27 insertions, 4 deletions
diff --git a/tests/manifest-roundtrip/buildfile b/tests/manifest-roundtrip/buildfile
index a2fb3ac..5cd296f 100644
--- a/tests/manifest-roundtrip/buildfile
+++ b/tests/manifest-roundtrip/buildfile
@@ -4,5 +4,11 @@
 
 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
 exe{driver}: test.roundtrip = manifest
diff --git a/tests/manifest-roundtrip/driver.cxx b/tests/manifest-roundtrip/driver.cxx
index 2068409..1f0b311 100644
--- a/tests/manifest-roundtrip/driver.cxx
+++ b/tests/manifest-roundtrip/driver.cxx
@@ -3,12 +3,29 @@
 // license   : MIT; see accompanying LICENSE file
 
 #include <cassert>
+
+#ifndef __cpp_lib_modules
+#include <string>
 #include <iostream>
+#endif
+
+// Other includes.
 
-#include <libbutl/utility.hxx>             // operator<<(ostream, exception)
-#include <libbutl/fdstream.hxx>
-#include <libbutl/manifest-parser.hxx>
-#include <libbutl/manifest-serializer.hxx>
+#ifdef __cpp_modules
+#ifdef __cpp_lib_modules
+import std.core;
+import std.io;
+#endif
+import butl.utility;             // operator<<(ostream, exception)
+import butl.fdstream;
+import butl.manifest_parser;
+import butl.manifest_serializer;
+#else
+#include <libbutl/utility.mxx>
+#include <libbutl/fdstream.mxx>
+#include <libbutl/manifest-parser.mxx>
+#include <libbutl/manifest-serializer.mxx>
+#endif
 
 using namespace std;
 using namespace butl;