diff --git a/test/cmake_subdir_test/CMakeLists.txt b/test/cmake_subdir_test/CMakeLists.txt
index 91ad663..036030b 100644
--- a/test/cmake_subdir_test/CMakeLists.txt
+++ b/test/cmake_subdir_test/CMakeLists.txt
@@ -7,6 +7,8 @@ cmake_minimum_required(VERSION 3.5...3.16)
 project(cmake_subdir_test LANGUAGES CXX)
 
 add_subdirectory(../.. boostorg/variant2)
+
+add_subdirectory(../../../assert boostorg/assert)
 add_subdirectory(../../../config boostorg/config)
 add_subdirectory(../../../mp11 boostorg/mp11)