diff --git a/radio/tests/interpolation/farrow/Makefile b/radio/tests/interpolation/farrow/Makefile
index 1fd6432..f7d68f1 100644
--- a/radio/tests/interpolation/farrow/Makefile
+++ b/radio/tests/interpolation/farrow/Makefile
@@ -7,7 +7,9 @@ LDFLAGS_release := -O3 -flto
 TARGET_ARCH := -march=native
 CXXFLAGS += -std=c++20
 
-CXX_SRCS += $(realpath .)/main.cpp
+PWD := $(realpath .)
+CXX_SRCS += $(PWD)/main.cpp
+CXX_SRCS += $(PWD)/test.cpp
 
 LIBS := -lstdc++ -lm -lpthread -lrt 
 LDFLAGS += $(TARGET_ARCH) $(LIBDIR)
diff --git a/radio/tests/interpolation/farrow/main.cpp b/radio/tests/interpolation/farrow/main.cpp
index 9317e40..652fc11 100644
--- a/radio/tests/interpolation/farrow/main.cpp
+++ b/radio/tests/interpolation/farrow/main.cpp
@@ -1,6 +1,10 @@
+#include <iostream>
 
+using namespace std;
+void test();
 
 int main()
 {
+	cout << "Halo, Welt!" << endl;
 	return 0;
 }
\ No newline at end of file