diff --git a/test_package/CMakeLists.txt b/test_package/CMakeLists.txt
index e57d1d8b..9b76bf9b 100644
--- a/test_package/CMakeLists.txt
+++ b/test_package/CMakeLists.txt
@@ -23,7 +23,17 @@
 cmake_minimum_required(VERSION 3.25)
 project(test_package LANGUAGES CXX)
 
+message(STATUS "MP_UNITS_BUILD_CXX_MODULES: ${MP_UNITS_BUILD_CXX_MODULES}")
+message(STATUS "MP_UNITS_API_STD_FORMAT: ${MP_UNITS_API_STD_FORMAT}")
+
 find_package(mp-units REQUIRED)
 
-add_executable(test_package test_package.cpp)
-target_link_libraries(test_package PRIVATE mp-units::mp-units)
+add_executable(test_package-headers test_package.cpp)
+target_compile_features(test_package-headers PRIVATE cxx_std_20)
+target_link_libraries(test_package-headers PRIVATE mp-units::mp-units)
+
+if(MP_UNITS_BUILD_CXX_MODULES)
+    add_executable(test_package test_package.cpp)
+    target_compile_features(test_package PRIVATE cxx_std_20)
+    target_link_libraries(test_package PRIVATE mp-units::mp-units)
+endif()
diff --git a/test_package/conanfile.py b/test_package/conanfile.py
index f81cf891..ef15fe3c 100644
--- a/test_package/conanfile.py
+++ b/test_package/conanfile.py
@@ -64,5 +64,8 @@ class TestPackageConan(ConanFile):
 
     def test(self):
         if can_run(self):
-            bin_path = os.path.join(self.cpp.build.bindirs[0], "test_package")
+            if self.dependencies["mp-units"].options.cxx_modules:
+                bin_path = os.path.join(self.cpp.build.bindirs[0], "test_package")
+                self.run(bin_path, env="conanrun")
+            bin_path = os.path.join(self.cpp.build.bindirs[0], "test_package-headers")
             self.run(bin_path, env="conanrun")