pick_from_list bypass user request if only one choice

Modify the pick_from_list() that normally issues a list of choices for the
user to pick one without issuing the pick list when there is only a
single choice and return that choice.  This bypasses the user having
to pick from a choice of one when there is only one choice.

Adds test for this and a change to the documentation to document this
behavior.

docs/pywbemcli/cmdshelp.rst

@@ -190,14 +190,14 @@ Help text for ``pywbemcli class`` (see :ref:`class command group`):
       -h, --help  Show this message and exit.
 
     Commands:
-      associators   List the classes associated with a class.
-      get           Get a class.
       enumerate     List top classes or subclasses of a class in a namespace.
-      tree          Show the subclass or superclass hierarchy for a class.
-      references    List the classes referencing a class.
+      get           Get a class.
+      delete        Delete a class.
       invokemethod  Invoke a method on a class.
+      references    List the classes referencing a class.
+      associators   List the classes associated with a class.
       find          List the classes with matching class names on the server.
-      delete        Delete a class.
+      tree          Show the subclass or superclass hierarchy for a class.
 
 
 .. _`pywbemcli class associators --help`:
@@ -708,13 +708,13 @@ Help text for ``pywbemcli connection`` (see :ref:`connection command group`):
       -h, --help  Show this message and exit.
 
     Commands:
-      show    Show a WBEM connection definition or the current connection.
-      list    List the WBEM connection definitions.
       export  Export the current connection.
+      show    Show a WBEM connection definition or the current connection.
+      delete  Delete a WBEM connection definition.
+      select  Select a WBEM connection definition as current or default.
       test    Test the current connection with a predefined WBEM request.
       save    Save the current connection to a new WBEM connection definition.
-      select  Select a WBEM connection definition as current or default.
-      delete  Delete a WBEM connection definition.
+      list    List the WBEM connection definitions.
 
 
 .. _`pywbemcli connection delete --help`:
@@ -1014,16 +1014,16 @@ Help text for ``pywbemcli instance`` (see :ref:`instance command group`):
       -h, --help  Show this message and exit.
 
     Commands:
-      count         Count the instances of each class with matching class name.
-      associators   List the instances associated with an instance.
+      enumerate     List the instances of a class.
       get           Get an instance of a class.
+      delete        Delete an instance of a class.
       create        Create an instance of a class in a namespace.
-      invokemethod  Invoke a method on an instance.
       modify        Modify properties of an instance.
+      associators   List the instances associated with an instance.
       references    List the instances referencing an instance.
-      enumerate     List the instances of a class.
+      invokemethod  Invoke a method on an instance.
       query         Execute a query on instances in a namespace.
-      delete        Delete an instance of a class.
+      count         Count the instances of each class with matching class name.
 
 
 .. _`pywbemcli instance associators --help`:
@@ -1728,8 +1728,8 @@ Help text for ``pywbemcli qualifier`` (see :ref:`qualifier command group`):
       -h, --help  Show this message and exit.
 
     Commands:
-      enumerate  List the qualifier declarations in a namespace.
       get        Get a qualifier declaration.
+      enumerate  List the qualifier declarations in a namespace.
 
 
 .. _`pywbemcli qualifier enumerate --help`:
@@ -1848,12 +1848,12 @@ Help text for ``pywbemcli server`` (see :ref:`server command group`):
       -h, --help  Show this message and exit.
 
     Commands:
-      info          Get information about the server.
-      centralinsts  List central instances of mgmt profiles on the server.
+      namespaces    List the namespaces of the server.
       interop       Get the Interop namespace of the server.
       brand         Get the brand of the server.
+      info          Get information about the server.
       profiles      List management profiles advertized by the server.
-      namespaces    List the namespaces of the server.
+      centralinsts  List central instances of mgmt profiles on the server.
 
 
 .. _`pywbemcli server brand --help`:

docs/pywbemcli/commands.rst

@@ -1145,7 +1145,9 @@ The ``connection delete`` command deletes a connection definition from the
 
 If the ``NAME`` argument is specified, the connection definition with that name
 is deleted. Otherwise, the command displays the list of connection definitions
-and prompts the user for picking the one to be deleted.
+and prompts the user to select the one to be deleted. If there is only a
+single connection, that connection is deleted without the user selection
+request.
 
 Example that deletes a connection definition by the specified name:
 
@@ -1267,7 +1269,9 @@ The ``connection select`` command selects a connection definition from the
 
 If the ``NAME`` argument is specified, the connection definition with that name
 is selected. Otherwise, the command displays the list of connection definitions
-and prompts the user for picking the one to be selected.
+and prompts the user to pick the one to be selected. If there is only a
+single connection, that connection is selected without the user
+request.
 
 If the ``--default`` command option is set, the connection definition in
 addition becomes the default connection, by marking it accordingly in the
@@ -1322,8 +1326,9 @@ Connection show command
 
 The ``connection show`` command shows information about a connection definition:
 
-* If ``NAME`` is ``?``, pywbemcli prompts the user for picking one and shows
-  the existing current connection.
+* If ``NAME`` is ``?``, pywbemcli prompts the user to select one and shows
+  the existing current connection. If there is only a single connection the
+  user selection is bypassed.
 * If ``NAME`` is specified, show the connection definition with that name.
 * If ``NAME`` is not specified, show the existing current connection.
 

docs/pywbemcli/features.rst

@@ -228,7 +228,8 @@ The instance name (INSTANCENAME argument) can be specified in two ways:
   :ref:`Interactively selecting INSTANCENAME command argument` (i.e.
   CLASSNAME.?). The namespace of the instance is the namespace specified with
   the ``-namespace``/``-n`` command option, or the default namespace of the
-  connection.
+  connection.  If there is only a single instance, that instance is selected
+  automaticaly with without user request.
 
 * By specifying the WBEM URI without keybindings and using the --key option
   to specify the keybindings ad defined in section

pywbemtools/pywbemcli/_common.py

@@ -116,6 +116,9 @@ def pick_one_from_list(context, options, title):
     Interactive component that displays a set of options (strings) and asks
     the user to select one.  Returns the item and index of the selected string.
 
+    If there is only a single item in the options, simply return that choice
+    without user intervention.
+
     Parameters:
       options:
         List of strings from which one will is to be selected
@@ -133,6 +136,12 @@ def pick_one_from_list(context, options, title):
     TODO: Possible Future This could be replaced by the python pick library
     that would use curses for the selection process.
     """
+
+    # If there is only a single choice, return that choice.
+    if len(options) == 1:
+        return options[0]
+
+    # Issue list of choices and prompt for user choice of index
     if context:
         context.spinner_stop()
 
@@ -142,8 +151,11 @@ def pick_one_from_list(context, options, title):
         index += 1
         click.echo('{}: {}'.format(index, str_))
     selection = None
-    msg = 'Input integer between 0 and {} or Ctrl-C to exit selection: ' \
+    msg = 'Input integer between 0 and {} or Ctrl-C to exit selection' \
         .format(index)
+
+    # Loop for valid user choice until valid choice made or selection aborted
+    # by user
     while True:
         try:
             selection_txt = click.prompt(msg)

tests/unit/test_common.py

@@ -446,6 +446,11 @@ def test_split_str(testcase, input_str, delimiter, exp_rtn):
      dict(options=[u'ZERO', u'ONE', u'TWO'], choices=['9', '-1', 'a', '2'],
           exp_rtn=u'TWO'),
      None, None, OK),
+
+    ('Verify returns correct choice with only single choice so no usr request',
+     dict(options=[u'ZERO'], choices=None,
+          exp_rtn=u'ZERO'),
+     None, None, OK),
 ]
 
 
@@ -458,15 +463,22 @@ def test_pick_one_from_list(testcase, options, choices, exp_rtn):
     Test for pick_one_from_list function. Uses mock patch to define return
     values from the mock.
     """
-    # setup mock for this test
-    mock_function = 'pywbemtools.pywbemcli.click.prompt'
-    with patch(mock_function, side_effect=choices) as mock_prompt:
-        # The code to be tested
-        title = "Test pick_one_from_list"
+    title = "Test pick_one_from_list"
+
+    # test option with only one choice bypasses user request
+    if not choices:
         context = ContextObj(None, None, None, None, None, None, None)
         act_rtn = pick_one_from_list(context, options, title)
-        context.spinner_stop()
-        assert mock_prompt.call_count == len(choices)
+    else:
+        # setup mock for this test
+        mock_function = 'pywbemtools.pywbemcli.click.prompt'
+        with patch(mock_function, side_effect=choices) as mock_prompt:
+            # The code to be tested
+            # fake context object
+            context = ContextObj(None, None, None, None, None, None, None)
+            act_rtn = pick_one_from_list(context, options, title)
+            context.spinner_stop()
+            assert mock_prompt.call_count == len(choices)
 
     # Ensure that exceptions raised in the remainder of this function
     # are not mistaken as expected exceptions

tests/unit/test_connection_cmds.py

@@ -599,11 +599,9 @@
       'file': {'before': 'exists', 'after': 'exists'}},
      MOCK_PROMPT0_FILE, OK],
 
-    ['Verify connection command delete with prompt that selects 0',
+    ['Verify connection command delete last one that  deletes w/o prompt',
      ['delete', ],
-     {'stdout': ['Select a connection or Ctrl_C to abort',
-                 '0: mocktest',
-                 'Input integer between 0 and 0 or Ctrl-C to exit selection:'],
+     {'stdout': ['Deleted  connection "mocktest'],
       'test': 'innows',
       'file': {'before': 'exists', 'after': 'none'}},
      MOCK_PROMPT0_FILE, OK],