test: remove --root option and fix TMP_DIRECTORY cleanup

The primary motivation here is to fix TMP_DIRECTORY cleanup prior to
running each test when the current working directory is not the test
subdirectory. Tests with failures would leave their TMP_DIRECTORY
directory behind for debugging, and repeated out-of-tree test runs
would have old temp directories. (This lead to e.g. T310-emacs.sh
hanging because emacs would prompt for overwriting files.)

We remove the likely anyway defunct --root test option while at it,
just to be on the safe side when doing 'rm -rf' on the TMP_DIRECTORY.

test/README

@@ -80,15 +80,6 @@ The following command-line options are available when running tests:
 	As the names depend on the tests' file names, it is safe to
 	run the tests with this option in parallel.
 
---root=<dir>::
-	This runs the testsuites specified under a separate directory.
-	However, caution is advised, as not all tests are maintained
-	with this relocation in mind, so some tests may behave
-	differently.
-
-	Pointing this argument at a tmpfs filesystem can improve the
-	speed of the test suite for some users.
-
 Certain tests require precomputed databases to complete. You can fetch these
 databases with
 

test/test-lib-common.sh

@@ -307,13 +307,9 @@ export PATH MANPATH
 
 # Test repository
 test="tmp.$(basename "$0" .sh)"
-test -n "$root" && test="$root/$test"
+TMP_DIRECTORY="$TEST_DIRECTORY/$test"
-case "$test" in
-/*) TMP_DIRECTORY="$test" ;;
- *) TMP_DIRECTORY="$TEST_DIRECTORY/$test" ;;
-esac
 test ! -z "$debug" || remove_tmp=$TMP_DIRECTORY
-rm -fr "$test" || {
+rm -rf "$TMP_DIRECTORY" || {
 	GIT_EXIT_OK=t
 	echo >&6 "FATAL: Cannot prepare test area"
 	exit 1

test/test-lib.sh

@@ -160,9 +160,6 @@ do
 		valgrind=t; verbose=t; shift ;;
 	--tee)
 		shift ;; # was handled already
-	--root=*)
-		root=$(expr "z$1" : 'z[^=]*=\(.*\)')
-		shift ;;
 	*)
 		echo "error: unknown test option '$1'" >&2; exit 1 ;;
 	esac