tests: clean after SANITY tests

Some of our tests try to make sure Git behaves sensibly in a
read-only directory, by dropping 'w' permission bit before doing a
test and then restoring it after it is done.  The latter is needed
for the test framework to clean after itself without leaving a
leftover directory that cannot be removed.

Ancient parts of tests however arrange the above with

	chmod a-w . &&
	... do the test ...
	status=$?
	chmod 775 .
	(exit $status)

which obviously would not work if the test somehow dies before it
has the chance to do "chmod 775".  Rewrite them by following a more
robust pattern recently written tests use, which is

	test_when_finished "chmod 775 ." &&
	chmod a-w . &&
	... do the test ...

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0001-init.sh

@@ -287,6 +287,7 @@ test_expect_success 'init notices EEXIST (2)' '
 '
 
 test_expect_success POSIXPERM,SANITY 'init notices EPERM' '
+	test_when_finished "chmod +w newdir" &&
 	rm -fr newdir &&
 	mkdir newdir &&
 	chmod -w newdir &&

t/t0070-fundamental.sh

@@ -19,8 +19,8 @@ test_expect_success 'mktemp to nonexistent directory prints filename' '
 
 test_expect_success POSIXPERM,SANITY 'mktemp to unwritable directory prints filename' '
 	mkdir cannotwrite &&
-	chmod -w cannotwrite &&
 	test_when_finished "chmod +w cannotwrite" &&
+	chmod -w cannotwrite &&
 	test_must_fail test-mktemp cannotwrite/testXXXXXX 2>err &&
 	grep "cannotwrite/test" err
 '

t/t1004-read-tree-m-u-wf.sh

@@ -179,6 +179,8 @@ test_expect_success 'funny symlink in work tree' '
 
 test_expect_success SANITY 'funny symlink in work tree, un-unlink-able' '
 
+	test_when_finished "chmod u+w a 2>/dev/null; rm -fr a b" &&
+
 	rm -fr a b &&
 	git reset --hard &&
 
@@ -188,10 +190,6 @@ test_expect_success SANITY 'funny symlink in work tree, un-unlink-able' '
 
 '
 
-# clean-up from the above test
-chmod a+w a 2>/dev/null
-rm -fr a b
-
 test_expect_success 'D/F setup' '
 
 	git reset --hard &&

t/t5537-fetch-shallow.sh

@@ -175,8 +175,8 @@ EOF
 
 test_expect_success POSIXPERM,SANITY 'shallow fetch from a read-only repo' '
 	cp -R .git read-only.git &&
-	find read-only.git -print | xargs chmod -w &&
 	test_when_finished "find read-only.git -type d -print | xargs chmod +w" &&
+	find read-only.git -print | xargs chmod -w &&
 	git clone --no-local --depth=2 read-only.git from-read-only &&
 	git --git-dir=from-read-only/.git log --format=%s >actual &&
 	cat >expect <<EOF &&

t/t7508-status.sh

@@ -1099,6 +1099,7 @@ EOF
 '
 
 test_expect_success POSIXPERM,SANITY 'status succeeds in a read-only repository' '
+	test_when_finished "chmod 775 .git" &&
 	(
 		chmod a-w .git &&
 		# make dir1/tracked stat-dirty
@@ -1108,9 +1109,6 @@ test_expect_success POSIXPERM,SANITY 'status succeeds in a read-only repository'
 		# make sure "status" succeeded without writing index out
 		git diff-files | grep dir1/tracked
 	)
-	status=$?
-	chmod 775 .git
-	(exit $status)
 '
 
 (cd sm && echo > bar && git add bar && git commit -q -m 'Add bar') && git add sm