Refactor tests related to ICEndpointCommandTest

[JuliaJoch]

The tests of ICEndpointCommandTest and several other older Test Classes have so many test smells that we are overwhelmed by all the changes that would be necessary in order to make this readable.

For example there is code duplication for setting up the email objects that will be tested which could be refactored into the setup method.
Also there are tests with a lot of assertions in one method.

[MrHenrik]

In addition the tearDown in ICEndpointCommandTest does not delete the folders which it builds