negative timezone offsets with a non-zero minutes field.
* tests/test_dates.py (DatetimeTests): Add tests for time zone
parsing. The test for HH:MM:SS time zones is disabled because we
don't currently support it.
Currently the second fails for negative offsets due to bugs in the
parser, and the third fails because it doesn't even try to parse second
offset values (as Python doesn't either).
* tests/*.py: use the DSN constructed in tests/__init__.py.
* tests/__init__.py: allow setting the host, port and user for the
DSN used by the tests through the environment.
return value for partially parsed time values.
* psycopg/typecast_mxdatetime.c (typecast_MXDATE_cast): return
NULL after setting DataError. Also, don't treat it as an error if
typecast_parse_time() returns 0 (as might happen if the remainder
of the string is " BC").
* psycopg/typecast_datetime.c (typecast_PYDATE_cast): return NULL
after setting DataError.
(typecast_PYDATETIME_cast): same here.
(typecast_PYTIME_cast): same here.
* tests/test_dates.py
(CommonDatetimeTestsMixin.test_parse_incomplete_date): test that
parsing incomplete date values results in DataError.
(CommonDatetimeTestsMixin.test_parse_incomplete_time): same for
times.
(CommonDatetimeTestsMixin.test_parse_incomplete_time): same for
datetimes.
* tests/test_dates.py: add tests for date/time typecasting and
adaption.
* psycopg/adapter_mxdatetime.c (mxdatetime_str): add support for
outputting BC dates (which involves switching them to one-based
dates). Also remove broken handling of microseconds.
* psycopg/typecast.c (typecast_parse_date): if the string ends
with "BC" adjust the year value to be a zero-based BC value as
used by mx.DateTime (datetime doesn't support BC dates).
(typecast_parse_time): ignore ' ', 'B' and 'C' in time strings
rather than treating them as part of the seconds part of the time.
