diff --git a/test/simulator/meson.build b/test/simulator/meson.build
index b53dce5..d65e286 100644
--- a/test/simulator/meson.build
+++ b/test/simulator/meson.build
@@ -1,5 +1,6 @@
 sim_sources = [
     'hei_sim_main.cpp',
+    'hei_sim_user_interface.cpp',
     '../../src/isolator/hei_isolator.cpp',
     '../../src/register/hei_hardware_register.cpp',
     '../../src/util/hei_bit_string.cpp',