from nose.tools import assert_equal
from datetime import datetime, date, time


class TestDateUtil():

    @classmethod
    def setup_class(cls):
        """This method is run once for each class before any tests are run"""
        cls.dt = datetime(cls.year, cls.month, cls.day,
                          cls.hour, cls.minute, cls.second)

    @classmethod
    def teardown_class(cls):
        """This method is run once for each class _after_ all tests are run"""

    def setUp(self):
        """This method is run once before _each_ test method is executed"""

    def teardown(self):
        """This method is run once after _each_ test method is executed"""

    year = 2015
    month = 1
    day = 20
    hour = 7
    minute = 28
    second = 15
    dt = None

    def test_datetime(self):
        assert_equal(self.dt.day, self.day)
        assert_equal(self.dt.minute, self.minute)
        assert_equal(self.dt.date(), date(self.year, self.month, self.day))
        assert_equal(self.dt.time(), time(self.hour, self.minute, self.second))

    def test_strftime(self):
        """Format the datetime string"""
        assert_equal(self.dt.strftime('%m/%d/%Y %H:%M'), '01/20/2015 07:28')

    def test_strptime(self):
        """Convert/parse string into datetime objects"""
        d = datetime(self.year, self.month, self.day)
        assert_equal(datetime.strptime('20150120', '%Y%m%d'), d)

    def test_datetime_replace(self):
        """When aggregating or grouping time series data, it is sometimes
        useful to replace fields of a series of datetimes such as zeroing
        out the minute and second fields."""
        dt = datetime(self.year, self.month, self.day, self.hour, 0, 0)
        assert_equal(self.dt.replace(minute=0, second=0), dt)