Sane use of test_expect_failure

Originally, test_expect_failure was designed to be the opposite
of test_expect_success, but this was a bad decision.  Most tests
run a series of commands that leads to the single command that
needs to be tested, like this:

    test_expect_{success,failure} 'test title' '
	setup1 &&
        setup2 &&
        setup3 &&
        what is to be tested
    '

And expecting a failure exit from the whole sequence misses the
point of writing tests.  Your setup$N that are supposed to
succeed may have failed without even reaching what you are
trying to test.  The only valid use of test_expect_failure is to
check a trivial single command that is expected to fail, which
is a minority in tests of Porcelain-ish commands.

This large-ish patch rewrites all uses of test_expect_failure to
use test_expect_success and rewrites the condition of what is
tested, like this:

    test_expect_success 'test title' '
	setup1 &&
        setup2 &&
        setup3 &&
        ! this command should fail
    '

test_expect_failure is redefined to serve as a reminder that
that test *should* succeed but due to a known breakage in git it
currently does not pass.  So if git-foo command should create a
file 'bar' but you discovered a bug that it doesn't, you can
write a test like this:

    test_expect_failure 'git-foo should create bar' '
        rm -f bar &&
        git foo &&
        test -f bar
    '

This construct acts similar to test_expect_success, but instead
of reporting "ok/FAIL" like test_expect_success does, the
outcome is reported as "FIXED/still broken".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t9106-git-svn-commit-diff-clobber.sh b/t/t9106-git-svn-commit-diff-clobber.sh
index 79b7968..f74ab12 100755
--- a/t/t9106-git-svn-commit-diff-clobber.sh
+++ b/t/t9106-git-svn-commit-diff-clobber.sh
@@ -24,11 +24,11 @@
 	rm -rf t.svn
 	"
 
-test_expect_failure 'commit conflicting change from git' "
+test_expect_success 'commit conflicting change from git' "
 	echo second line from git >> file &&
 	git commit -a -m 'second line from git' &&
-	git-svn commit-diff -r1 HEAD~1 HEAD $svnrepo
-	" || true
+	! git-svn commit-diff -r1 HEAD~1 HEAD $svnrepo
+"
 
 test_expect_success 'commit complementing change from git' "
 	git reset --hard HEAD~1 &&
@@ -39,7 +39,7 @@
 	git-svn commit-diff -r2 HEAD~1 HEAD $svnrepo
 	"
 
-test_expect_failure 'dcommit fails to commit because of conflict' "
+test_expect_success 'dcommit fails to commit because of conflict' "
 	git-svn init $svnrepo &&
 	git-svn fetch &&
 	git reset --hard refs/remotes/git-svn &&
@@ -52,8 +52,8 @@
 	rm -rf t.svn &&
 	echo 'fourth line from git' >> file &&
 	git commit -a -m 'fourth line from git' &&
-	git-svn dcommit
-	" || true
+	! git-svn dcommit
+	"
 
 test_expect_success 'dcommit does the svn equivalent of an index merge' "
 	git reset --hard refs/remotes/git-svn &&
@@ -76,15 +76,15 @@
 	rm -rf t.svn
 	"
 
-test_expect_failure 'multiple dcommit from git-svn will not clobber svn' "
+test_expect_success 'multiple dcommit from git-svn will not clobber svn' "
 	git reset --hard refs/remotes/git-svn &&
 	echo new file >> new-file &&
 	git update-index --add new-file &&
 	git commit -a -m 'new file' &&
 	echo clobber > file &&
 	git commit -a -m 'clobber' &&
-	git svn dcommit
-	" || true
+	! git svn dcommit
+	"
 
 
 test_expect_success 'check that rebase really failed' 'test -d .dotest'