First a simple smoke test first, next generate messages with multiple
email address variants and check the behaviour of deduplication
schemes with these.
The files (test) scripts source (with builtin command `.`) provides
information which the scripts depend, and without the `source` to
succeed allowing script to continue may lead to dangerous situations
(e.g. rm -rf "${undefined_variable}"/*).
At the end of all source (.) lines construct ' || exit 1' was added;
In our case the script script will exit if it cannot find (or read) the
file to be sourced. Additionally script would also exits if the last
command of the sourced file exited nonzero.
When no --output option were given, change default to display senders
only.
When only --count option is given, display senders (in contrary to not
displaying anything).
Document that --count with --sort=**order** is not supported option
combination.
Clean up some whitespace in the documentation.
One test updated to have --output=count without sender nor recipient
output option.
This filters out duplicate addresses from address command output.
It also also adds tests for the address command.
The code here is an extended version of a patch from Jani Nikula.
