test-lib: make test_expect_code a test command

Change test_expect_code to be a normal test command instead of a
top-level command.

As a top-level command it would fail in cases like:

    test_expect_code 1 'phoney' '
        foo && bar && (exit 1)
    '

Here the test might incorrectly succeed if "foo" or "bar" happened to
fail with exit status 1. Instead we now do:

    test_expect_success 'phoney' '
        foo && bar && test_expect_code 1 "(exit 1)"
    '

Which will only succeed if "foo" and "bar" return status 0, and "(exit
1)" returns status 1.  Note that test_expect_code has been made slightly
noisier, as it reports the exit code it receives even upon success.

Some test code in t0000-basic.sh relied on the old semantics of
test_expect_code to test the test_when_finished command. I've
converted that code to use an external test similar to the TODO test I
added in v1.7.3-rc0~2^2~3.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/README

@@ -395,13 +395,6 @@ library for your script to use.
    Like test_expect_success this function can optionally use a three
    argument invocation with a prerequisite as the first argument.
 
- - test_expect_code [<prereq>] <code> <message> <script>
-
-   Analogous to test_expect_success, but pass the test if it exits
-   with a given exit <code>
-
- test_expect_code 1 'Merge with d/f conflicts' 'git merge "merge msg" B master'
-
  - test_debug <script>
 
    This takes a single argument, <script>, and evaluates it only
@@ -482,6 +475,15 @@ library for your script to use.
 	    'Perl API' \
 	    "$PERL_PATH" "$TEST_DIRECTORY"/t9700/test.pl
 
+ - test_expect_code <exit-code> <command>
+
+   Run a command and ensure that it exits with the given exit code.
+   For example:
+
+	test_expect_success 'Merge with d/f conflicts' '
+		test_expect_code 1 git merge "merge msg" B master
+	'
+
  - test_must_fail <git-command>
 
    Run a git command and ensure it fails in a controlled way.  Use

t/t0000-basic.sh

@@ -130,22 +130,57 @@ test_expect_success 'tests clean up after themselves' '
     test_when_finished clean=yes
 '
 
-cleaner=no
-test_expect_code 1 'tests clean up even after a failure' '
-    test_when_finished cleaner=yes &&
-    (exit 1)
-'
-
-if test $clean$cleaner != yesyes
+if test $clean != yes
 then
-	say "bug in test framework: cleanup commands do not work reliably"
+	say "bug in test framework: basic cleanup command does not work reliably"
 	exit 1
 fi
 
-test_expect_code 2 'failure to clean up causes the test to fail' '
-    test_when_finished "(exit 2)"
+test_expect_success 'tests clean up even on failures' "
+    mkdir failing-cleanup &&
+    (cd failing-cleanup &&
+    cat >failing-cleanup.sh <<EOF &&
+#!$SHELL_PATH
+
+test_description='Failing tests with cleanup commands'
+
+# Point to the t/test-lib.sh, which isn't in ../ as usual
+TEST_DIRECTORY=\"$TEST_DIRECTORY\"
+. \"\$TEST_DIRECTORY\"/test-lib.sh
+
+test_expect_success 'tests clean up even after a failure' '
+    touch clean-after-failure &&
+    test_when_finished rm clean-after-failure &&
+    (exit 1)
+'
+
+test_expect_success 'failure to clean up causes the test to fail' '
+    test_when_finished \"(exit 2)\"
 '
 
+test_done
+EOF
+    chmod +x failing-cleanup.sh &&
+    test_must_fail ./failing-cleanup.sh >out 2>err &&
+    ! test -s err &&
+    ! test -f \"trash directory.failing-cleanup/clean-after-failure\" &&
+sed -e 's/Z$//' >expect <<\EOF &&
+not ok - 1 tests clean up even after a failure
+#	Z
+#	    touch clean-after-failure &&
+#	    test_when_finished rm clean-after-failure &&
+#	    (exit 1)
+#	Z
+not ok - 2 failure to clean up causes the test to fail
+#	Z
+#	    test_when_finished \"(exit 2)\"
+#	Z
+# failed 2 among 2 test(s)
+1..2
+EOF
+    test_cmp expect out)
+"
+
 ################################################################
 # Basics of the basics
 

t/t1504-ceiling-dirs.sh

@@ -9,8 +9,9 @@ test_prefix() {
 }
 
 test_fail() {
-	test_expect_code 128 "$1: prefix" \
-	"git rev-parse --show-prefix"
+	test_expect_success "$1: prefix" '
+		test_expect_code 128 git rev-parse --show-prefix
+	'
 }
 
 TRASH_ROOT="$PWD"

t/t6020-merge-df.sh

@@ -20,7 +20,9 @@ echo "file dir" > dir &&
 git add dir &&
 git commit -m "File: dir"'
 
-test_expect_code 1 'Merge with d/f conflicts' 'git merge "merge msg" B master'
+test_expect_success 'Merge with d/f conflicts' '
+	test_expect_code 1 git merge "merge msg" B master
+'
 
 test_expect_success 'F/D conflict' '
 	git reset --hard &&

t/test-lib.sh

@@ -473,24 +473,6 @@ test_expect_success () {
 	echo >&3 ""
 }
 
-test_expect_code () {
-	test "$#" = 4 && { prereq=$1; shift; } || prereq=
-	test "$#" = 3 ||
-	error "bug in the test script: not 3 or 4 parameters to test-expect-code"
-	if ! test_skip "$@"
-	then
-		say >&3 "expecting exit code $1: $3"
-		test_run_ "$3"
-		if [ "$?" = 0 -a "$eval_ret" = "$1" ]
-		then
-			test_ok_ "$2"
-		else
-			test_failure_ "$@"
-		fi
-	fi
-	echo >&3 ""
-}
-
 # test_external runs external test scripts that provide continuous
 # test output about their progress, and succeeds/fails on
 # zero/non-zero exit code.  It outputs the test output on stdout even
@@ -658,6 +640,28 @@ test_might_fail () {
 	return 0
 }
 
+# Similar to test_must_fail and test_might_fail, but check that a
+# given command exited with a given exit code. Meant to be used as:
+#
+#	test_expect_success 'Merge with d/f conflicts' '
+#		test_expect_code 1 git merge "merge msg" B master
+#	'
+
+test_expect_code () {
+	want_code=$1
+	shift
+	"$@"
+	exit_code=$?
+	if test $exit_code = $want_code
+	then
+		echo >&2 "test_expect_code: command exited with $exit_code: $*"
+		return 0
+	else
+		echo >&2 "test_expect_code: command exited with $exit_code, we wanted $want_code $*"
+		return 1
+	fi
+}
+
 # test_cmp is a helper function to compare actual and expected output.
 # You can use it like:
 #