Added add_deprecated_argument tests

letsencrypt/le_util.py

@@ -6,8 +6,9 @@ import logging
 import os
 import platform
 import re
-import subprocess
 import stat
+import subprocess
+import sys
 
 from letsencrypt import errors
 
@@ -258,7 +259,7 @@ def safe_email(email):
         return False
 
 
-def add_deprecated_argument(add_argument, argument_name):
+def add_deprecated_argument(add_argument, argument_name, nargs):
     """Adds a deprecated argument with the name argument_name.
 
     Deprecated arguments are not shown in the help. If they are used on
@@ -268,11 +269,14 @@ def add_deprecated_argument(add_argument, argument_name):
     :param callable add_argument: Function that adds arguments to an
         argument parser/group.
     :param str argument_name: Name of deprecated argument.
+    :param nargs: Value for nargs when adding the argument to argparse.
 
     """
     class ShowWarning(argparse.Action):
         """Action to log a warning when an argument is used."""
         def __call__(self, unused1, unused2, unused3, option_string=None):
-            print "Use of {0} is deprecated".format(option_string)
+            sys.stderr.write(
+                "Use of {0} is deprecated\n".format(option_string))
 
-    add_argument(argument_name, action=ShowWarning, help=argparse.SUPPRESS)
+    add_argument(argument_name, action=ShowWarning,
+                 help=argparse.SUPPRESS, nargs=nargs)

letsencrypt/tests/le_util_test.py

@@ -1,8 +1,10 @@
 """Tests for letsencrypt.le_util."""
+import argparse
 import errno
 import os
 import shutil
 import stat
+import StringIO
 import tempfile
 import unittest
 
@@ -284,5 +286,42 @@ class SafeEmailTest(unittest.TestCase):
             self.assertFalse(self._call(addr), "%s failed." % addr)
 
 
+class AddDeprecatedArgumentTest(unittest.TestCase):
+    """Test add_deprecated_argument."""
+    def setUp(self):
+        self.parser = argparse.ArgumentParser()
+
+    def _call(self, argument_name, nargs):
+        from letsencrypt.le_util import add_deprecated_argument
+
+        add_deprecated_argument(self.parser.add_argument, argument_name, nargs)
+
+    def test_warning_no_arg(self):
+        self._call("--old-option", 0)
+        stderr = self._get_argparse_warnings(["--old-option"])
+        self.assertTrue("--old-option is deprecated" in stderr)
+
+    def test_warning_with_arg(self):
+        self._call("--old-option", 1)
+        stderr = self._get_argparse_warnings(["--old-option", "42"])
+        self.assertTrue("--old-option is deprecated" in stderr)
+
+    def _get_argparse_warnings(self, args):
+        stderr = StringIO.StringIO()
+        with mock.patch("letsencrypt.le_util.sys.stderr", new=stderr):
+            self.parser.parse_args(args)
+        return stderr.getvalue()
+
+    def test_help(self):
+        self._call("--old-option", 2)
+        stdout = StringIO.StringIO()
+        with mock.patch("letsencrypt.le_util.sys.stdout", new=stdout):
+            try:
+                self.parser.parse_args(["-h"])
+            except SystemExit:
+                pass
+        self.assertTrue("--old-option" not in stdout.getvalue())
+
+
 if __name__ == "__main__":
     unittest.main()  # pragma: no cover