rewrite test suite
Created by: mkhl
this changeset splits the test suite into several smaller test cases and uses bats to support write and run them. besides functionality that was covered before it adds a test for passing arguments to xdg-terminal-exec and one for handling a large desktop entry file.
oh and 20bc2142 makes the TryExec
check posix compliant and less noisy when it fails.
n.b. that desktop entry is mostly a copy of the current one used by gnome-terminal, and x-t-e takes about 2.5 seconds to handle it on my machine. that provided motivation for me to rewrite x-t-e altogether (in rust) but i figure the test suite would help here too.