2 files changed, 35 insertions, 6 deletions
diff --git a/tests/progress/buildfile b/tests/progress/buildfile
index 19e85c0..d8cb6d6 100644
--- a/tests/progress/buildfile
+++ b/tests/progress/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/progress/driver.cxx b/tests/progress/driver.cxx
index 0ff68f0..c8c2080 100644
--- a/tests/progress/driver.cxx
+++ b/tests/progress/driver.cxx
@@ -4,20 +4,43 @@
 
 #ifndef _WIN32
 #  include <unistd.h> // write()
-
-#  include <thread> // this_thread::sleep_for()
 #else
 #  include <libbutl/win32-utility.hxx>
-
 #  include <io.h> //_write()
 #endif
 
+#include <cassert>
+
+#ifndef __cpp_lib_modules
+#include <string>
 #include <cstddef>  // size_t
 #include <iostream>
+#ifndef _WIN32
+#  include <thread> // this_thread::sleep_for()
+#endif
+#endif
 
-#include <libbutl/process.hxx>
-#include <libbutl/fdstream.hxx>    // fdnull(), stderr_fd()
-#include <libbutl/diagnostics.hxx>
+// Other includes.
+
+#ifdef __cpp_modules
+#ifdef __cpp_lib_modules
+import std.core;
+import std.io;
+#ifndef _WIN32
+//@@ MOD TODO import std.threading;
+#endif
+#endif
+import butl.process;
+import butl.fdstream;
+import butl.diagnostics;
+
+import butl.optional;     // @@ MOD Clang should not be necessary.
+import butl.small_vector; // @@ MOD Clang should not be necessary.
+#else
+#include <libbutl/process.mxx>
+#include <libbutl/fdstream.mxx>    // fdnull(), stderr_fd()
+#include <libbutl/diagnostics.mxx>
+#endif
 
 using namespace std;
 using namespace butl;