DateFormatter shows microseconds instead of %f for years <= 1900

azjps · azjps · commit b208e4ab9ae7 · 2015-02-24T18:33:05.000-05:00
Add a simple test for DateFormatter. closes #3179 Change-Id: Idff9d06cbc6dc00a3cb8dcf113983d82dbdd3fde
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -426,33 +426,35 @@ def _findall(self, text, substr):
             i = j + 1
         return sites
 
-    # Dalke: I hope I did this math right.  Every 28 years the
-    # calendar repeats, except through century leap years excepting
-    # the 400 year leap years.  But only if you're using the Gregorian
-    # calendar.
-
     def strftime(self, dt, fmt):
         fmt = self.illegal_s.sub(r"\1", fmt)
         fmt = fmt.replace("%s", "s")
         if dt.year > 1900:
             return cbook.unicode_safe(dt.strftime(fmt))
 
+        # Dalke: I hope I did this math right.  Every 28 years the
+        # calendar repeats, except through century leap years excepting
+        # the 400 year leap years.  But only if you're using the Gregorian
+        # calendar.
+
         year = dt.year
         # For every non-leap year century, advance by
         # 6 years to get into the 28-year repeat cycle
         delta = 2000 - year
         off = 6 * (delta // 100 + delta // 400)
         year = year + off
 
-        # Move to around the year 2000
+        # Move to between the years 1973 and 2000
         year = year + ((2000 - year) // 28) * 28
-        timetuple = dt.timetuple()
-        s1 = time.strftime(fmt, (year,) + timetuple[1:])
+
+        s1 = dt.replace(year=year).strftime(fmt)
         sites1 = self._findall(s1, str(year))
 
-        s2 = time.strftime(fmt, (year + 28,) + timetuple[1:])
+        s2 = dt.replace(year=year + 28).strftime(fmt)
         sites2 = self._findall(s2, str(year + 28))
 
+        # Generate timestamp string for year and year+28, and replace
+        # instances of respective years in same location with dt's year
         sites = []
         for site in sites1:
             if site in sites2:
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -158,6 +158,39 @@ def test_DateFormatter():
     ax.autoscale_view()
     fig.autofmt_xdate()
 
+def test_date_formatter_strftime():
+    """
+    Tests that DateFormatter matches datetime.strftime,
+    check microseconds for years before 1900 for bug #3179.
+    """
+    def test_strftime_fields(dt):
+        """For datetime object dt, check DateFormatter fields"""
+        formatter = mdates.DateFormatter("%d %m %Y %H %I %M %S %f")
+        # Compute date fields without using datetime.strftime,
+        # since datetime.strftime does not work before year 1900
+        formatted_date_str = (
+            "{day:02d} {month:02d} {full_year:4d} "
+            "{hour24:02d} {hour12:02d} {minute:02d} {second:02d} "
+            "{microsecond:06d}".format(
+            # %w Sunday=0, weekday() Monday=0
+            # Following do not work because of issue #3179
+            # weekday = str((dt.weekday() + 1) % 7),  # %w    {weekday}
+            # year = dt.year % 100,                   # %y    {year:02d}
+            # weeknum = dt.isocalendar()[1],          # %U/%W {weeknum:02d}
+            day = dt.day,
+            month = dt.month,
+            full_year = dt.year,
+            hour24 = dt.hour,
+            hour12 = ((dt.hour-1) % 12) + 1,
+            minute = dt.minute,
+            second = dt.second,
+            microsecond = dt.microsecond))
+        assert_equal(formatter.strftime(dt, formatter.fmt), formatted_date_str)
+
+    for year in range(1, 3000, 71):
+        # Iterate through random set of years
+        test_strftime_fields(datetime.datetime(year, 1, 1))
+        test_strftime_fields(datetime.datetime(year, 2, 3, 4, 5, 6, 123456))
 
 def test_date_formatter_callable():
     scale = -11
