Fixed repr for FixedOffsetTimezone for offsets west of UTC (negative)

The offset displayed was always positive and somewhat confusing. The
offset displayed now is the offset that the instance was created
with.

Also added some tests for initialisation.

lib/tz.py

@@ -50,8 +50,9 @@ class FixedOffsetTimezone(datetime.tzinfo):
             self._name = name
 
     def __repr__(self):
+        offset_mins = self._offset.seconds // 60 + self._offset.days * 24 * 60
         return "psycopg2.tz.FixedOffsetTimezone(offset=%r, name=%r)" \
-            % (self._offset.seconds // 60, self._name)
+            % (offset_mins, self._name)
 
     def utcoffset(self, dt):
         return self._offset

tests/test_dates.py

@@ -25,7 +25,7 @@
 import math
 import unittest
 import psycopg2
-from psycopg2.tz import FixedOffsetTimezone
+from psycopg2.tz import FixedOffsetTimezone, ZERO
 from testconfig import dsn
 
 class CommonDatetimeTestsMixin:
@@ -513,6 +513,25 @@ class FromTicksTestCase(unittest.TestCase):
             time(0, 11, 59, 999920))
 
 
+class FixedOffsetTimezoneTests(unittest.TestCase):
+
+    def test_init_with_no_args(self):
+        tzinfo = FixedOffsetTimezone()
+        self.assert_(tzinfo._offset is ZERO)
+        self.assert_(tzinfo._name is None)
+
+    def test_repr_with_positive_offset(self):
+        tzinfo = FixedOffsetTimezone(5 * 60)
+        self.assertEqual(repr(tzinfo), "psycopg2.tz.FixedOffsetTimezone(offset=300, name=None)")
+
+    def test_repr_with_negative_offset(self):
+        tzinfo = FixedOffsetTimezone(-5 * 60)
+        self.assertEqual(repr(tzinfo), "psycopg2.tz.FixedOffsetTimezone(offset=-300, name=None)")
+
+    def test_repr_with_name(self):
+        tzinfo = FixedOffsetTimezone(name="FOO")
+        self.assertEqual(repr(tzinfo), "psycopg2.tz.FixedOffsetTimezone(offset=0, name='FOO')")
+
 def test_suite():
     return unittest.TestLoader().loadTestsFromName(__name__)