FRIEND_TEST(TestCaseName, TestName);

// foo.h
#include <gtest/gtest_prod.h>

// Defines FRIEND_TEST.
class Foo {
  ...
 private:
  FRIEND_TEST(FooTest, BarReturnsZeroOnNull);
  int Bar(void* x);
};

// foo_test.cc
...
TEST(FooTest, BarReturnsZeroOnNull) {
  Foo foo;
  EXPECT_EQ(0, foo.Bar(NULL));
  // Uses Foo's private member Bar().
}

#define FRIEND_TEST(test_case_name, test_name)
friend class test_case_name##_##test_name##_Test

friend class FooTest_BarReturnsZeroOnNull_Test;

// foo.h
#include <gtest/gtest_prod.h>

class FooTest_BarReturnsZeroOnNull_Test;

// Defines FRIEND_TEST.
class my_namespace::Foo {
  ...
 private:
  FRIEND_TEST(::FooTest, BarReturnsZeroOnNull);
  int Bar(void* x);
};

// foo_test.cc
using namespace my_namespace;

...
TEST(FooTest, BarReturnsZeroOnNull) {
  Foo foo;
  EXPECT_EQ(0, foo.Bar(NULL));
  // Uses Foo's private member Bar().
}