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>

1 files changed, 6 insertions, 6 deletions

diff --git a/t/t5600-clone-fail-cleanup.sh b/t/t5600-clone-fail-cleanup.sh
index 1776b377f3..acf34cec8f 100755
--- a/t/t5600-clone-fail-cleanup.sh
+++ b/t/t5600-clone-fail-cleanup.sh
@@ -11,13 +11,13 @@ remove the directory before attempting a clone again.'
 
 . ./test-lib.sh
 
-test_expect_failure \
+test_expect_success \
     'clone of non-existent source should fail' \
-    'git-clone foo bar'
+    '! git-clone foo bar'
 
-test_expect_failure \
+test_expect_success \
     'failed clone should not leave a directory' \
-    'cd bar'
+    '! test -d bar'
 
 # Need a repo to clone
 test_create_repo foo
@@ -27,9 +27,9 @@ test_create_repo foo
 
 # source repository given to git-clone should be relative to the
 # current path not to the target dir
-test_expect_failure \
+test_expect_success \
     'clone of non-existent (relative to $PWD) source should fail' \
-    'git-clone ../foo baz'
+    '! git-clone ../foo baz'
 
 test_expect_success \
     'clone should work now that source exists' \