I have the following code defining a path where generated files can be placed:

```
fn gen_test_dir() -> tempdir::TempDir {                                        
    tempdir::TempDir::new_in(Path::new("/tmp"), "filesyncer-tests").unwrap()   
} 

```

This function is defined in `tests/lib.rs`, used in the tests in that file and I would also like to use it in the unit tests located in `src/lib.rs`. 

Is this possible to achieve without compiling the utility functions into the non-test binary and without duplicating code?