diff --git a/src/modules/motion.cpp b/src/modules/motion.cpp
index ef62a74..edc6e79 100644
--- a/src/modules/motion.cpp
+++ b/src/modules/motion.cpp
@@ -62,10 +62,6 @@ bool Motion::QueueEmpty() const {
     return true;
 }
 
-bool Motion::QueueEmpty(config::Axis axis) const {
-    return axisData[axis].ctrl.QueueEmpty();
-}
-
 void Motion::AbortPlannedMoves(bool halt) {
     for (uint8_t i = 0; i != NUM_AXIS; ++i)
         axisData[i].ctrl.AbortPlannedMoves(halt);
diff --git a/src/modules/motion.h b/src/modules/motion.h
index 783226b..472b9b7 100644
--- a/src/modules/motion.h
+++ b/src/modules/motion.h
@@ -239,7 +239,14 @@ public:
 
     /// @returns true if all planned moves have been finished for one axis
     /// @param axis requested
-    bool QueueEmpty(Axis axis) const;
+    bool QueueEmpty(Axis axis) const
+#ifndef UNITTEST
+    {
+        return axisData[axis].ctrl.QueueEmpty();
+    }
+#else
+        ;
+#endif
 
     /// @returns false if new moves can still be planned for one axis
     /// @param axis axis requested
diff --git a/tests/unit/CMakeLists.txt b/tests/unit/CMakeLists.txt
index 53fd3a5..51c5944 100644
--- a/tests/unit/CMakeLists.txt
+++ b/tests/unit/CMakeLists.txt
@@ -1,6 +1,8 @@
 # first, let's create a symbolic target for all tests
 add_custom_target(tests)
 
+add_compile_definitions(UNITTEST)
+
 # include catch_discover_tests function from Catch2
 include(${Catch2_SOURCE_DIR}/contrib/Catch.cmake)