Unit test for decommission error

[alinadonisa]

We should add an unit test that would test that the decommission will throw an error on failure

[alinadonisa]

@udnay I have spoke with @chrislovecnm and because this task implies a bit of refactory on the decommission logic we will implement this later

[udnay]

Makes sense, can you just write some pseudocode for what the test should look like?