Question

I have a C++11 project with many googletest unit tests looking like

TEST_F(GTest, testSomething) {
    int64_t n = 42;
    // following code depends on input size n
    ...
}

Rather than having a local constant n in each test, I’d like to be able to set the input size from one location, preferably the command line:

./RunMyProgram --gtest_filter=* --n=1000

The main should look like:

int main(int argc, char **argv) {

     // TODO: parse command line argument n here

    INFO("=== starting unit tests ===");

    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();

}

With what should I replace ? in my test functions?

TEST_F(GTest, testSomething) {
    int64_t n = ?;
    // following code depends on input size n
    ...
}

Answer 1

First of all, if you use the same value/parameter in more than one of your test functions, consider to use Fixtures.

What you are trying to do for me looks like a “value parameterized test”. I guess thats rather common in testing world, and – tadaa, Google Test has a chapter in its advanced guide, called “Value Parameterized Test” (and oh, it uses fixtures).