diff -r 462470859e57 Lib/test/test_calendar.py
--- a/Lib/test/test_calendar.py	Sat Apr 26 19:01:47 2014 -0400
+++ b/Lib/test/test_calendar.py	Sun Apr 27 13:28:25 2014 -0700
@@ -496,6 +496,16 @@
         new_october = calendar.TextCalendar().formatmonthname(2010, 10, 10)
         self.assertEqual(old_october, new_october)
 
+    def test_locale_calendar_formatweekday(self):
+        # formatweekday uses different day names based on the available width.
+        cal = calendar.LocaleTextCalendar(locale='en_US')
+        # For short widths, a centered, abbreviated name is used.
+        self.assertEqual(cal.formatweekday(0, 5), " Mon ")
+        # For really short widths, even the abbreviated name is truncated.
+        self.assertEqual(cal.formatweekday(0, 2), "Mo")
+        # For long widths, the full day name is used.
+        self.assertEqual(cal.formatweekday(0, 10), "  Monday  ")
+
     def test_itermonthdates(self):
         # ensure itermonthdates doesn't overflow after datetime.MAXYEAR
         # see #15421
diff -r 462470859e57 Misc/ACKS
--- a/Misc/ACKS	Sat Apr 26 19:01:47 2014 -0400
+++ b/Misc/ACKS	Sun Apr 27 13:28:25 2014 -0700
@@ -400,6 +400,7 @@
 Dan Finnie
 Nils Fischbeck
 Frederik Fix
+Sean Fleming
 Matt Fleming
 Hernán Martínez Foffani
 Artem Fokin