Unify the subtests by requiring test_begin_subtest before
test_expect_success. (Similar change for test_expect_code will
follow.)
This increases clarity in the test scripts by having a separate line
for the start of the subtest with the heading, and makes it possible
to simplify the test infrastructure by making all subtests similar.
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.
Change #!/bin/bash at start of tests to "#!/usr/bin/env bash". That way
systems running on bash < 4 can prepend bash >= 4 to path before
running the tests.
Git-style tests (test_expect_success etc.) suppress stdout and stderr
unless -v is given. Notmuch-style tests (created by test_begin_subtest
and test_expect_equal) do not have this behavior so implement it the
same.
Additionally, for both test styles, the test-lib.sh is changed so that
the content of suppressed stdout and stderr is shown in case of failed
test.
Finally a test for this functionality is added to basic tests.
