Fix traceback with no arguments on Python 3.

Fixes bug 1424277.

1 files changed, 48 insertions, 0 deletions

diff --git a/tests/unittests/test_cli.py b/tests/unittests/test_cli.py
new file mode 100644
index 00000000..ba447f87
--- /dev/null
+++ b/tests/unittests/test_cli.py
@@ -0,0 +1,48 @@
+import imp
+import sys
+
+import six
+
+from . import helpers as test_helpers
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+
+class TestCLI(test_helpers.FilesystemMockingTestCase):
+
+    def setUp(self):
+        super(TestCLI, self).setUp()
+        self.stderr = six.StringIO()
+        self.patchStdoutAndStderr(stderr=self.stderr)
+        self.sys_exit = mock.MagicMock()
+        self.patched_funcs.enter_context(
+            mock.patch.object(sys, 'exit', self.sys_exit))
+
+    def _call_main(self):
+        self.patched_funcs.enter_context(
+            mock.patch.object(sys, 'argv', ['cloud-init']))
+        cli = imp.load_module(
+            'cli', open('bin/cloud-init'), '', ('', 'r', imp.PY_SOURCE))
+        try:
+            return cli.main()
+        except:
+            pass
+
+    def test_no_arguments_shows_usage(self):
+        self._call_main()
+        self.assertIn('usage: cloud-init', self.stderr.getvalue())
+
+    def test_no_arguments_exits_2(self):
+        exit_code = self._call_main()
+        if self.sys_exit.call_count:
+            self.assertEqual(mock.call(2), self.sys_exit.call_args)
+        else:
+            self.assertEqual(2, exit_code)
+
+    def test_no_arguments_shows_error_message(self):
+        self._call_main()
+        self.assertIn('cloud-init: error: too few arguments',
+                      self.stderr.getvalue())