We put some effort into testing the built copy rather than some
installed copy. On the other hand for people like packagers, testing
the installed copy is also of interest.
When NOTMUCH_TEST_INSTALLED is set to a nonempty value, tests do not
require a built notmuch tree or running configure.
Some of the tests marked as broken when running against installed
notmuch are probably fixable.
Turns out round trip tests didn't really round trip anything. Broken
by yours truly in 971cdc72cd ("test: make it possible to have
multiple corpora"). Ooops.
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.
All test scripts to be executed are now named as T\d\d\d-name.sh,
numers in increments of 10.
This eases adding new tests and developers to see which are test scripts
that are executed by test suite and in which order.
