Add test for the behavior of --help

Recursive over ostree and all subcommands, and check that --help
is supported, properly outputs to standard out, and exits
with a 0 exit status. Check that for commands with subcommands,
they produce the help output to standard error when run with no arguments.

https://bugzilla.gnome.org/show_bug.cgi?id=737194

Makefile-tests.am

@@ -27,6 +27,7 @@ testfiles = test-basic \
 	test-archivez \
 	test-remote-add \
         test-commit-sign \
+	test-help \
 	test-libarchive \
 	test-pull-archive-z \
 	test-pull-corruption \

tests/libtest.sh

@@ -78,6 +78,12 @@ assert_file_has_content () {
     fi
 }
 
+assert_file_empty() {
+    if test -s "$1"; then
+	echo 1>&2 "File '$1' is not empty"; exit 1
+    fi
+}
+
 setup_test_repository () {
     mode=$1
     shift

tests/test-help.sh

@@ -0,0 +1,59 @@
+#!/bin/bash
+#
+# Copyright (C) 2014 Owen Taylor <otaylor@redhat.com>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+set -e
+
+. $(dirname $0)/libtest.sh
+
+echo "1..1"
+
+echo "Testing:" 1>&2
+test_recursive() {
+    local cmd=$1
+    echo "$cmd" 1>&2
+    $cmd --help 1>out 2>err
+    # --help message goes to standard output
+    assert_file_has_content out "[Uu]sage"
+    assert_file_has_content out "$cmd"
+    assert_file_empty err
+    builtins=`sed -n '/^Builtin commands/,/^[^ ]/p' <out | tail -n +2`
+    if [ "$builtins" != "" ] ; then
+        # A command with subcommands
+        # Running the command without a subcommand should produce the help output, but fail
+        set +e
+        $cmd 1>out 2>err
+        if [ $? = 0 ] ; then
+	    echo 1>&2 "missing subcommand but 0 exit status"; exit 1
+        fi
+        set -e
+        # error message and usage goes to standard error
+        assert_file_has_content err "[Uu]sage"
+        assert_file_has_content err "$cmd"
+        assert_file_has_content err "Builtin commands"
+        assert_file_empty out
+
+        for subcmd in $builtins ; do
+            test_recursive "$cmd $subcmd"
+        done
+    fi
+}
+
+test_recursive ostree
+
+echo "ok help option is properly supported"