tests: do not require Git to be built when testing an installed Git

We really only need the test helpers to be built in the worktree in that
case, but that is not what we test for.

On the other hand it is a perfect opportunity to verify that
`GIT_TEST_INSTALLED` points to a working Git.

So let's test the appropriate Git executable. While at it, also adjust
the error message in the `GIT_TEST_INSTALLED` case.

This patch is best viewed with `-w --patience`.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/test-lib.sh b/t/test-lib.sh
index 93883580a8b30482fdcccdddc724c92aeeef3f9d..3d3a65ed0ec5c1bfe11f3afed3c17c174c954c2e 100644 (file)
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -51,10 +51,15 @@ export LSAN_OPTIONS
 
 ################################################################
 # It appears that people try to run tests without building...
-"$GIT_BUILD_DIR/git" >/dev/null
+"${GIT_TEST_INSTALLED:-$GIT_BUILD_DIR}/git" >/dev/null
 if test $? != 1
 then
-       echo >&2 'error: you do not seem to have built git yet.'
+       if test -n "$GIT_TEST_INSTALLED"
+       then
+               echo >&2 "error: there is no working Git at '$GIT_TEST_INSTALLED'"
+       else
+               echo >&2 'error: you do not seem to have built git yet.'
+       fi
        exit 1
 fi