Merge pull request #612 from python-cmd2/select_zero

Fixed bug in cmd2.Cmd.select() when user enters 0 or negative number

Author: tleonhardt

CHANGELOG.md

@@ -1,4 +1,6 @@
 ## 0.9.7 (TBD, 2018)
+* Bug Fixes
+    * Fixed bug when user chooses a zero or negative index when calling ``Cmd.select()``
 * Enhancements
     * **cmdloop** now only attempts to register a custom signal handler for SIGINT if running in the main thread
     * commands run as a result of ``default_to_shell`` being **True** now run via ``do_shell()`` and are saved

cmd2/cmd2.py

@@ -2780,6 +2780,8 @@ def select(self, opts: Union[str, List[str], List[Tuple[Any, Optional[str]]]], p
 
             try:
                 choice = int(response)
+                if choice < 1:
+                    raise IndexError
                 result = fulloptions[choice - 1][0]
                 break
             except (ValueError, IndexError):

tests/test_cmd2.py

@@ -1344,11 +1344,11 @@ def test_select_options(select_app):
     # And verify the expected output to stdout
     assert out == expected
 
-def test_select_invalid_option(select_app):
+def test_select_invalid_option_too_big(select_app):
     # Mock out the input call so we don't actually wait for a user's response on stdin
     m = mock.MagicMock(name='input')
     # If side_effect is an iterable then each call to the mock will return the next value from the iterable.
-    m.side_effect = ['3', '1']  # First pass and invalid selection, then pass a valid one
+    m.side_effect = ['3', '1']  # First pass an invalid selection, then pass a valid one
     builtins.input = m
 
     food = 'fish'
@@ -1368,6 +1368,30 @@ def test_select_invalid_option(select_app):
     # And verify the expected output to stdout
     assert out == expected
 
+def test_select_invalid_option_too_small(select_app):
+    # Mock out the input call so we don't actually wait for a user's response on stdin
+    m = mock.MagicMock(name='input')
+    # If side_effect is an iterable then each call to the mock will return the next value from the iterable.
+    m.side_effect = ['0', '1']  # First pass an invalid selection, then pass a valid one
+    builtins.input = m
+
+    food = 'fish'
+    out = run_cmd(select_app, "eat {}".format(food))
+    expected = normalize("""
+   1. sweet
+   2. salty
+'0' isn't a valid choice. Pick a number between 1 and 2:
+{} with sweet sauce, yum!
+""".format(food))
+
+    # Make sure our mock was called exactly twice with the expected arguments
+    arg = 'Sauce? '
+    calls = [mock.call(arg), mock.call(arg)]
+    m.assert_has_calls(calls)
+
+    # And verify the expected output to stdout
+    assert out == expected
+
 def test_select_list_of_strings(select_app):
     # Mock out the input call so we don't actually wait for a user's response on stdin
     m = mock.MagicMock(name='input', return_value='2')