can I debug my cpp code using linux gdb? if yes how can I keep break points on a function which is called over an object.

example:

class test_gdb
{
public:
void testFun(void)
{
cout << "this is test function"<<endl;
}
};

int main(void)
{
test_gdb testObj;
testObj.testFun();
}

here if I want to keep a break point at testFun, how can I do it. I tried but with break testFun but it didn't work.