feat: extract test code

CMakeLists.txt

@@ -12,7 +12,7 @@ include(ExportCompileCommands)
 configure_file("${PROJECT_SOURCE_DIR}/include/version.h.in"
                "${PROJECT_BINARY_DIR}/include/version.h")
 
-add_executable(hello src/main.cpp)
+add_executable(hello src/main.cpp src/null.cpp)
 target_compile_features(hello PUBLIC cxx_std_20)
 
 target_include_directories(hello PRIVATE "${PROJECT_BINARY_DIR}/include")

src/main.cpp

@@ -1,36 +1,16 @@
 #include <cstdlib>
 #include <iostream>
-#include <type_traits>
 
 #include "version.h"
 
-void call_test(char *) { std::cout << "call_test(char *) called" << std::endl; }
+#include "null.h"
-
-void call_test(int) { std::cout << "call_test(int) called" << std::endl; }
 
 int main(int argc, char **argv) {
 
   std::cout << "Running " << PROJECT_NAME << ", version " << VERSION << "\n"
             << std::endl;
 
-  if (std::is_same<decltype(NULL), decltype(0)>::value) {
+  null::test();
-    std::cout << "NULL == 0" << std::endl;
-  }
-
-  if (std::is_same<decltype(NULL), decltype((void *)0)>::value) {
-    std::cout << "NULL == (void *)0" << std::endl;
-  }
-
-  if (std::is_same<decltype(NULL), decltype(__null)>::value) {
-    std::cout << "NULL == __null" << std::endl;
-  }
-
-  if (std::is_same<decltype(NULL), std::nullptr_t>::value) {
-    std::cout << "NULL == nullptr" << std::endl;
-  }
-
-  call_test(0);
-  call_test(nullptr);
 
   std::cout << "\nExiting" << std::endl;
 

src/null.cpp

@@ -0,0 +1,29 @@
+#include <iostream>
+#include <type_traits>
+
+#include "null.h"
+
+void call_test(char *) { std::cout << "call_test(char *) called" << std::endl; }
+
+void call_test(int) { std::cout << "call_test(int) called" << std::endl; }
+
+void null::test() {
+  if (std::is_same<decltype(NULL), decltype(0)>::value) {
+    std::cout << "NULL == 0" << std::endl;
+  }
+
+  if (std::is_same<decltype(NULL), decltype((void *)0)>::value) {
+    std::cout << "NULL == (void *)0" << std::endl;
+  }
+
+  if (std::is_same<decltype(NULL), decltype(__null)>::value) {
+    std::cout << "NULL == __null" << std::endl;
+  }
+
+  if (std::is_same<decltype(NULL), std::nullptr_t>::value) {
+    std::cout << "NULL == nullptr" << std::endl;
+  }
+
+  call_test(0);
+  call_test(nullptr);
+}

src/null.h

@@ -0,0 +1,5 @@
+#pragma once
+
+namespace null {
+void test();
+};