How can I use member functions of google unit test case in thread defined in the unit test?

Question

I have a google unit test where I've defined a few functions in it. It looks like the following

class MyUnitTest {
protected:
    void SetUp() override;
    void TearDown() override;
    void MyFunction();
};

And I have a test case such as the following:

TEST_F(MyUnitTest, MyCustomTest)
{
   std::thread t1(MainThreadFunction);
   t1.join();
}

void MainThreadFunction()
{
   MyFunction(); // <--- I cannot call this, as it is out of scope.
}

My question is, without making MyFunction a static function, there a way to call MyFunction within MainThreadFunction()? I tried std::bind as suggested here, but it didn't work for me:

Usage threads in google tests

Answer 1

I think the easiest solution would be to use a lambda instead of MainThreadFunction:

[Demo]

#include <gtest/gtest.h>
#include <iostream>

class MyUnitTest : public ::testing::Test {
protected:
    void SetUp() override {}
    void TearDown() override {}
    void MyFunction() { std::cout << "\n***** MyFunction *****\n\n"; }
};

TEST_F(MyUnitTest, MyCustomTest) {
   std::thread t1([this](){ this->MyFunction(); });
   t1.join();
}

int main() {
    ::testing::InitGoogleTest();
    [[maybe_unused]] auto i{ RUN_ALL_TESTS() };
}

In case you need to use MainThreadFunction, have it receive a pointer to a member function. Notice, in this case, I had to make MyFunction public:

[Demo]

#include <gtest/gtest.h>
#include <iostream>

class MyUnitTest : public ::testing::Test {
protected:
    void SetUp() override {}
    void TearDown() override {}
public:
    void MyFunction() { std::cout << "\n***** MyFunction *****\n\n"; }
};

void MainThreadFunction(MyUnitTest* ut, void (MyUnitTest::*MyFunctionPtr)()) {
    (ut->*MyFunctionPtr)();
}

TEST_F(MyUnitTest, MyCustomTest) {
   std::thread t1(MainThreadFunction, this, &MyUnitTest::MyFunction);
   t1.join();
}

int main() {
    ::testing::InitGoogleTest();
    [[maybe_unused]] auto i{ RUN_ALL_TESTS() };
}