add dates and times functions in util

Author: gabrielaznar

climada/util/dates_times.py

@@ -0,0 +1,27 @@
+"""
+Define functions to handle dates nad times in climada
+"""
+import datetime as dt
+
+def date_to_str(date):
+    """ Compute date string in ISO format from input datetime ordinal int.
+
+    Parameters:
+        date (int): input datetime ordinal
+
+    Returns:
+        str
+    """
+    return dt.date.fromordinal(date).isoformat()
+
+def str_to_date(date):
+    """ Compute datetime ordinal int from input date string in ISO format.
+
+    Parameters:
+        date (str): idate string in ISO format, e.g. '2018-04-06'
+
+    Returns:
+        int
+    """
+    year, mounth, day = (int(val) for val in date.split('-'))
+    return dt.date(year, mounth, day).toordinal()

climada/util/test/test_dates_times.py

@@ -0,0 +1,23 @@
+"""
+Test of dates_times module
+"""
+import datetime as dt
+import unittest
+
+import climada.util.dates_times as u_dt
+
+class TestDateString(unittest.TestCase):
+    """Test date functions """
+    def test_date_to_str_pass(self):
+        """ Test _date_to_str function"""
+        ordinal_date = dt.datetime.toordinal(dt.datetime(2018, 4, 6))
+        self.assertEqual('2018-04-06', u_dt.date_to_str(ordinal_date))
+
+    def test_str_to_date_pass(self):
+        """ Test _date_to_str function"""
+        date = 730000
+        self.assertEqual(u_dt.str_to_date(u_dt.date_to_str(date)), date)
+
+# Execute Tests
+TESTS = unittest.TestLoader().loadTestsFromTestCase(TestDateString)
+unittest.TextTestRunner(verbosity=2).run(TESTS)