add a test project for testing this action

test/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.0)
+project(test)
+add_executable(hello_world hello_world.cpp)

test/hello_world.cpp

@@ -0,0 +1,6 @@
+#include <iostream>
+
+int main() {
+  std::cout << "Hello world!" << std::endl;
+  return 0;
+}