nohup: write unit tests to improve coverage #1857
Description
We almost don't have tests for nohup. We should have more:
https://codecov.io/gh/uutils/coreutils/tree/master/src/uu/nohup/src
Should be added here:
https://github.com/uutils/coreutils/blob/master/tests/by-util/test_nohup.rs