Apply suggestions from code review

Author: terryjreedy

Lib/idlelib/editor.py

@@ -1338,24 +1338,6 @@ def set_indentation_params(self, is_py_src, guess=True):
                 self.usetabs = False
         self.set_tk_tabwidth(self.tabwidth)
 
-    def delete_trail_char_and_space(self, want, chars, tabwidth):
-        chars = chars[:-1]  # remove last character unconditionally
-        current_pos = 0
-        ncharsretained = 0
-        for char in chars:
-            if char == '\t':
-                current_pos = (current_pos // tabwidth + 1) * tabwidth
-            else:
-                current_pos += 1
-            if current_pos > want:
-                break
-            ncharsretained += 1
-        for i in range(ncharsretained, len(chars)):
-            if chars[i] not in " \t":
-                ncharsretained = i + 1
-        chars = chars[:ncharsretained]
-        return chars
-
     def smart_backspace_event(self, event):
         text = self.text
         first, last = self.get_selection_indices()
@@ -1384,10 +1366,13 @@ def smart_backspace_event(self, event):
         assert have > 0
         want = ((have - 1) // self.indentwidth) * self.indentwidth
         # Debug prompt is multilined....
-        oldchars = chars
-        chars = self.delete_trail_char_and_space(want, chars, tabwidth)
-        ncharsdeleted = len(oldchars) - len(chars)
-        have = len(chars.expandtabs(tabwidth))
+        ncharsdeleted = 0
+        while True:
+            chars = chars[:-1]
+            ncharsdeleted = ncharsdeleted + 1
+            have = len(chars.expandtabs(tabwidth))
+            if have <= want or chars[-1] not in " \t":
+                break
         text.undo_block_start()
         text.delete("insert-%dc" % ncharsdeleted, "insert")
         if have < want:

Lib/idlelib/idle_test/test_editor.py

@@ -238,64 +238,5 @@ def test_rclick(self):
         pass
 
 
-class DeleteWantTest(unittest.TestCase):
-
-    data = [
-        ("abcde" + 10000 * "\t" + 10000 * " ", [
-            (30000, 4, "abcde" + 7499 * "\t"),
-            (41005, 4, "abcde" + 10000 * "\t" + 1001 * " "),
-            (3, 4, "abcde"),
-            (6, 4, "abcde"),
-            (30002, 4, "abcde" + 7499 * "\t"),
-        ]),
-        ("abcde\tabd\t\t", [
-            (7, 4, "abcde\tabd"),
-            (12, 4, "abcde\tabd\t"),
-            (13, 4, "abcde\tabd\t"),
-            (16, 4, "abcde\tabd\t"),
-        ]),
-        ("abcde\tabd\t \ta", [
-            (7, 4, "abcde\tabd"),
-            (12, 4, "abcde\tabd\t"),
-            (13, 4, "abcde\tabd\t "),
-            (16, 4, "abcde\tabd\t \t"),
-        ]),
-        ("    ", [
-            (2, 2, "  "),
-        ]),
-    ]
-
-    def mock_delete_trail_char_and_space(self, want, chars, tabwidth):
-        ncharsdeleted = 0
-        while True:
-            chars = chars[:-1]
-            ncharsdeleted = ncharsdeleted + 1
-            have = len(chars.expandtabs(tabwidth))
-            if have <= want or chars[-1] not in " \t":
-                break
-        return chars
-
-    def do_tests(self):
-        ew = Editor()
-        for dat in self.data:
-            test_str = dat[0]
-            for da in dat[1]:
-                with self.subTest(want=da[0], tabwidth=da[1], input=test_str):
-                    res = ew.delete_trail_char_and_space(da[0], test_str, da[1])
-                    self.assertEqual(res, da[2])
-
-    def test_delete_trail_char_and_space(self):
-        with unittest.mock.patch.object(Editor, '__init__', return_value=None):
-            initial_time_new = time.time()
-            self.do_tests()
-            time_new = time.time() - initial_time_new
-
-            with unittest.mock.patch.object(Editor, 'delete_trail_char_and_space', self.mock_delete_trail_char_and_space):
-                initial_time_old = time.time()
-                self.do_tests()
-                time_old = time.time() - initial_time_old
-
-            self.assertGreaterEqual(time_old / time_new, 10)
-
 if __name__ == '__main__':
     unittest.main(verbosity=2)