t: document test_lazy_prereq

index 53e5b4a710..3ce9f5a393 100644 --- a/t/README +++ b/t/README @@ -818,7 +818,7 @@ Skipping tests -------------- If you need to skip tests you should do so by using the three-arg form -of the test_* functions (see the "Test harness library" section +of the test_expect_* functions (see the "Test harness library" section below), e.g.: test_expect_success PERL 'I need Perl' ' @@ -965,6 +965,27 @@ see test-lib-functions.sh for the full list and their options. test_done fi + - test_lazy_prereq <prereq> <script> + + Declare the way to determine if a test prerequisite <prereq> is + satisified or not, but delay the actual determination until the + prerequisite is actually used by "test_have_prereq" or the + three-arg form of the test_expect_* functions. For example, this + is how the SYMLINKS prerequisite is declared to see if the platform + supports symbolic links: + + test_lazy_prereq SYMLINKS ' + ln -s x y && test -h y + ' + + The script is lazily invoked when SYMLINKS prerequisite is first + queried by either "test_have_prereq SYMLINKS" or "test_expect_* + SYMLINKS ...". The script is run in a temporary directory inside + a subshell, so you do not have to worry about removing temporary + files you create there. When the script exits with status 0, the + prerequisite is set. Exiting with non-zero status makes the + prerequisite unsatisified. + - test_expect_code <exit-code> <command> Run a command and ensure that it exits with the given exit code.