diff --git a/otto.sh b/otto.sh
index 1dd70ad..0a7a4a5 100755
--- a/otto.sh
+++ b/otto.sh
@@ -116,7 +116,7 @@ add_new_module () {
 
     sed "s/module_name/${modname}/" $MODULE_DIR/CMakeLists.txt > $modsrc_dir/CMakeLists.txt
 
-    sed "s/module_name/${modname}/" $MODULE_DIR/test_module_name.c > $modtest_dir/test_${modname}.c
+    sed "s/module_name/${modname}/" $MODULE_DIR/test_module_name.cpp > $modtest_dir/test_${modname}.cpp
     sed "s/module_name/${modname}/" $MODULE_DIR/TestCMakeLists.txt > $modtest_dir/CMakeLists.txt
    
     # Add the module to the cmake lists files.