test: add a test for zodb commmad and help driver

zodbtools/test/test_zodb.py

+# Copyright (C) 2019  Nexedi SA and Contributors.
+#                     Jerome Perrin <jerome@nexedi.com>
+#
+# This program is free software: you can Use, Study, Modify and Redistribute
+# it under the terms of the GNU General Public License version 3, or (at your
+# option) any later version, as published by the Free Software Foundation.
+#
+# You can also Link and Combine this program with other software covered by
+# the terms of any of the Free Software licenses or any of the Open Source
+# Initiative approved licenses and Convey the resulting work. Corresponding
+# source of such a combination shall include the source code for all other
+# software used.
+#
+# This program is distributed WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See COPYING file for full licensing terms.
+# See https://www.nexedi.com/licensing for rationale and options.
+
+import sys
+try:
+    from unittest import mock
+except ImportError:
+    # BBB python2
+    import mock
+
+import pytest
+
+from zodbtools import zodb
+from zodbtools import help as help_module
+
+
+def test_main(capsys):
+    with mock.patch.object(sys, 'argv', ('zodb', )), \
+         pytest.raises(SystemExit) as excinfo:
+        zodb.main()
+    assert "Zodb is a tool for managing ZODB databases." in capsys.readouterr(
+    ).err
+    assert excinfo.value.args == (2, )
+
+
+@pytest.mark.parametrize(
+    "help_topic",
+    tuple(zodb.command_dict) + tuple(help_module.topic_dict))
+def test_help(capsys, help_topic):
+    with mock.patch.object(sys, 'argv', ('zodb', 'help', help_topic)), \
+         pytest.raises(SystemExit) as excinfo:
+        zodb.main()
+    assert capsys.readouterr().out
+    assert "" == capsys.readouterr().err
+    assert excinfo.value.args == (0, )