Re: [PATCH] Allow Overriding GIT_BUILD_DIR

Junio C Hamano [off-list ref] writes:

Ok, this is getting closer. We use GIT_BUILD_DIR to find out crucial bits
of the build environment in order to run tests, like the binaries being
tested that are in $GIT_BUILD_DIR/bin-wrappers, but we set GIT_BUILD_DIR
always to one level above where the test script being run is (because they
are typically t/t1234-name.sh).  By making them able to name GIT_BUILD_DIR
directly to a place that is different from a level above "$TEST_DIRECTORY",
a test script can live anywhere.

Right.

There are two more things that worries me a bit.

One is what TEST_DIRECTORY should mean in the new world order.  

That and its interaction with GIT_BUILD_DIR really confused me when I
was trying to get the subtree tests to work.  I think they could use
either a bit more documentation or a bit more separation of purpose.
I'm not sure which.

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 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.

I am willing to add comments (as a separate patch?) as I figure out what
these things do.  Perhaps I'll write up a patch and get feedback to spur
discussion so I can come to better understanding.  :)

quoted

@@ -55,6 +55,7 @@ unset $(perl -e '
 		.*_TEST
 		PROVE
 		VALGRIND
+                BUILD_DIR

A funny    indentation found here.

Will fix.

quoted

+if test -z "$GIT_BUILD_DIR"
+then
+	# We allow tests to override this, in case they want to run tests
+	# outside of t/, e.g. for running tests on the test library
+	# itself.

# For in-tree test scripts, this is one level above the TEST_DIRECTORY
# (t/), but a test script that lives outside t/ can set this variable to
# point at the right place so that it can find t/ directory that house
# test helpers like lib-pager*.sh and test vectors like t4013/.

This is good commentary.  Will add.

                                -Dave