Introduced input_select_items

alternative and more flexibile implementation to fulfil #1723
Added test case for new input method

beets/ui/__init__.py

@@ -367,6 +367,31 @@ def input_yn(prompt, require=False):
     return sel == 'y'
 
 
+def input_select_items(prompt, items, rep):
+    """Prompts the user to use all, none or some of the items
+    Will return the list of items the user selected
+    prompt: prompt to use for all and for selective choice
+    items: full list of items
+    rep: function which represents an item to the user
+         is called with the item as argument
+         function is responsive for newline at input
+    """
+    out_items = []
+    choice = input_options(
+        ('y', 'n', 's'), False,
+        '%s (Yes/No/Selective)?' % prompt)
+    print()
+    if choice == 'y':
+        out_items = items
+    elif choice == 's':
+        for item in items:
+            rep(item)
+            if input_yn('%s (y/n)?' % prompt, True):
+                out_items.append(item)
+            print()
+    return out_items
+
+
 # Human output formatting.
 
 def human_bytes(size):

test/test_ui_init.py

@@ -21,6 +21,56 @@ from test._common import unittest
 from beets import ui
 
 
+class InputMethodsTest(_common.TestCase):
+    def setUp(self):
+        super(InputMethodsTest, self).setUp()
+        self.io.install()
+
+    def _print_helper(self, s):
+        print(s)
+
+    def _print_helper2(self, s, prefix):
+        print(prefix, s)
+
+    def test_input_select_items(self):
+        full_items = ['1', '2', '3', '4', '5']
+
+        # Test no
+        self.io.addinput('n')
+        items = ui.input_select_items(
+            "Prompt", full_items, self._print_helper)
+        self.assertEqual(items, [])
+
+        # Test yes
+        self.io.addinput('y')
+        items = ui.input_select_items(
+            "Prompt", full_items, self._print_helper)
+        self.assertEqual(items, full_items)
+
+        # Test selective 1
+        self.io.addinput('s')
+        self.io.addinput('n')
+        self.io.addinput('y')
+        self.io.addinput('n')
+        self.io.addinput('y')
+        self.io.addinput('n')
+        items = ui.input_select_items(
+            "Prompt", full_items, self._print_helper)
+        self.assertEqual(items, ['2', '4'])
+
+        # Test selective 2
+        self.io.addinput('s')
+        self.io.addinput('y')
+        self.io.addinput('y')
+        self.io.addinput('n')
+        self.io.addinput('y')
+        self.io.addinput('n')
+        items = ui.input_select_items(
+            "Prompt", full_items,
+            lambda s: self._print_helper2(s, "Prefix"))
+        self.assertEqual(items, ['1', '2', '4'])
+
+
 class InitTest(_common.LibTestCase):
     def setUp(self):
         super(InitTest, self).setUp()