Re: [PATCH] Allow Overriding GIT_BUILD_DIR

[Thomas Rast <trast@inf.ethz.ch>]

greened@obbligato.org (David A. Greene) writes:

> Junio C Hamano <gitster@pobox.com> writes:
>
>> We use it to find where the test-lib.sh and other lib-*.sh helper
>> definitions are, also we use it to find large-ish test vectors like
>> t3900/ and t4013/.  If an external test script t1234-git-subtree.sh
>> wants to use a separate file to keep its own helper definitions, how
>> should it name it?  It cannot be relative to TEST_DIRECTORY that is
>> typically "t/".  It cannot be relative to "../" as TRASH_DIRECTORY
>> where the script runs, as the --root option may move it elsewhere on
>> the filesystem (and is the reason TEST_DIRECTORY variable exists in
>> the first place).
>
> I must admit I am still confused about what these variables do even
> after reading this explanation several times.  I have a pretty good
> idea what TRASH_DIRECTORY is.
>
>> And how well does an external test script work with the --root option that
>> moves the TEST_DIRECTORY?

I think Junio meant TRASH_DIRECTORY here, too.

> I have no idea.  I didn't even know about --root and I still don't know
> what it does.  It would be helpful to have some commentary about
> options.

--root tells the tests where to put its TRASH_DIRECTORY and is
frequently used to place it on a tmpfs (such as /dev/shm) as that gives
the tests a *huge* speed boost.

That is, if I say

  ./t5510-fetch.sh --root=/dev/shm

then the "main test repo" aka TRASH_DIRECTORY is

  /dev/shm/trash directory.t5510-fetch

-- 
Thomas Rast
trast@{inf,student}.ethz.ch