How should I unit test functions with many subfunctions?

I'm looking to better understand I should test functions that have many substeps or subfunctions.

Let's say I have the functions

// Modify the state of class somehow
public void DoSomething(){
    DoSomethingA();
    DoSomethingB();
    DoSomethingC();
}

Every function here is public. Each subfunction has 2 paths. So to test every path for DoSomething() I'd have 2*2*2 = 8 tests. By writing 8 tests for DoSomething() I will have indirectly tested the subfunctions too.

So should I be testing like this, or instead write unit tests for each of the subfunctions and then only write 1 test case that measures the final state of the class after DoSomething() and ignore all the possible paths? A total of 2+2+2+1 = 7 tests. But is it bad then that the DoSomething() test case will depend on the other unit test cases to have complete coverage?