How to create a JNIEnv mock in C/C++

#include "jni.h"
#include <iostream>

jint JNICALL MockGetVersion(JNIEnv *)
{
  return 23;
}

JNINativeInterface_ jnini = {
  0, 0, 0, 0, //4 reserved pointers
  MockGetVersion
};

// class Foo { public static native void bar(); }
void Java_Foo_bar(JNIEnv* jni, jclass)
{
  std::cout << jni->GetVersion() << std::endl;
}

int main()
{
  JNIEnv_ myjni = {&jnini};
  Java_Foo_bar(&myjni, 0);
  return 0;
}