diff --git a/test/meson.build b/test/meson.build
index 8963593..7c7b513 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -50,6 +50,7 @@
                                    '../pid/util.cpp'],
     'pid_stepwisecontroller_unittest': ['../pid/ec/stepwise.cpp',
                                         '../pid/stepwisecontroller.cpp',
+                                        '../pid/tuning.cpp',
                                         '../pid/util.cpp'],
     'pid_thermalcontroller_unittest': ['../pid/ec/pid.cpp',
                                        '../pid/pidcontroller.cpp',