Added some new functions to dates, with appropriate tests.

Author: domdfcoding

domdf_python_tools/dates.py

@@ -33,6 +33,7 @@
 
 # stdlib
 import datetime
+from collections import OrderedDict
 
 # 3rd party
 try:
@@ -153,6 +154,101 @@ def utc_timestamp_to_datetime(utc_timestamp, output_tz=None):
 
 		new_datetime = datetime.datetime.fromtimestamp(utc_timestamp, output_tz)
 		return new_datetime.astimezone(output_tz)
+	
+	
+	# List of months and their 3-character shortcodes.
+	months = OrderedDict(
+			Jan="January",
+			Feb="February",
+			Mar="March",
+			Apr="April",
+			May="May",
+			Jun="June",
+			Jul="July",
+			Aug="August",
+			Sep="September",
+			Oct="October",
+			Nov="November",
+			Dec="December",
+			)
+	
+	
+	def parse_month(month):
+		"""
+		Converts an integer or shorthand month into the full month name
+
+		:param month:
+		:type month: str or int
+
+		:return:
+		:rtype: str
+		"""
+		
+		try:
+			month = int(month)
+		except ValueError:
+			try:
+				return months[month.capitalize()[:3]]
+			except KeyError:
+				raise ValueError("Unrecognised month value")
+		
+		# Only get here if first try succeeded
+		if 0 < month <= 12:
+			return list(months.values())[month - 1]
+		else:
+			raise ValueError("Unrecognised month value")
+	
+	
+	def get_month_number(month):
+		"""
+		Returns the number of the given month. If ``month`` is already a
+		number between 1 and 12 it will be returned immediately.
+
+		:param month: The month to convert to a number
+		:type month: str or int
+
+		:return: The number of the month
+		:rtype:
+		"""
+		
+		if isinstance(month, int):
+			if 0 < month <= 12:
+				return month
+			else:
+				raise ValueError("The given month is not recognised.")
+		else:
+			month = parse_month(month)
+			return list(months.values()).index(month) + 1
+	
+	
+	def check_date(month, day, leap_year=True):
+		"""
+		Returns ``True`` if the day number is valid for the given month.
+		Note that this will return ``True`` for the 29th Feb. If you don't
+		want this behaviour set ``leap_year`` to ``False``.
+
+		:param month: The month to test
+		:type month: str, int
+		:param day: The day number to test
+		:type day: int
+		:param leap_year: Whether to return ``True`` for 29th Feb
+		:type leap_year: bool
+
+		:return: ``True`` if the date is valid
+		:rtype: bool
+		"""
+		
+		# Ensure day is an integer
+		day = int(day)
+		month = get_month_number(month)
+		year = 2020 if leap_year else 2019
+		
+		try:
+			datetime.date(year, month, day)
+			return True
+		except ValueError:
+			return False
+
 
 except ImportError:
 	import warnings

tests/test_dates.py

@@ -12,13 +12,15 @@
 
 # 3rd party
 import pytz
+import pytest
 
 # this package
 from domdf_python_tools import dates
 
 test_date = datetime.datetime(1996, 10, 13, 2, 20).replace(tzinfo=pytz.utc)
 today = datetime.datetime.utcnow().replace(tzinfo=pytz.utc)  # make sure UTC
 
+
 # TODO: travis matrix to test without pytz installed
 # TODO: test get_timezone
 
@@ -29,7 +31,7 @@ def test_utc_offset():
 	assert dates.get_utc_offset("Europe/London", test_date) == datetime.timedelta(0, 3600)
 	assert dates.get_utc_offset("Africa/Algiers", test_date) == datetime.timedelta(0, 3600)
 	# TODO: Finish
-
+	
 	# Check that the correct UTC offsets are given for common timezones for today
 	assert dates.get_utc_offset("US/Pacific", today) == datetime.timedelta(-1, 61200)
 	assert dates.get_utc_offset("Europe/London", today) == datetime.timedelta(0, 3600)
@@ -39,36 +41,39 @@ def test_utc_offset():
 	assert dates.get_utc_offset("US/Pacific") == datetime.timedelta(-1, 61200)
 	assert dates.get_utc_offset("Europe/London") == datetime.timedelta(0, 3600)
 	assert dates.get_utc_offset("Africa/Algiers") == datetime.timedelta(0, 3600)
-	# TODO: Finish
+
+
+# TODO: Finish
 
 
 def test_converting_timezone():
 	# No matter what timezone we convert to the timestamp should be the same
 	for tz in pytz.all_timezones:
-		assert test_date.astimezone(dates.get_timezone(tz, test_date)).timestamp() == test_date.timestamp() == 845173200.0
-
+		assert test_date.astimezone(
+			dates.get_timezone(tz, test_date)).timestamp() == test_date.timestamp() == 845173200.0
+		
 		if dates.get_utc_offset(tz, test_date):  # otherwise the timezone stayed as UTC
 			assert test_date.astimezone(dates.get_timezone(tz, test_date)).hour != test_date.hour
 
 		# And again with today's date
 		assert today.astimezone(dates.get_timezone(tz, today)).timestamp() == today.timestamp()
 		if dates.get_utc_offset(tz, today):  # otherwise the timezone stayed as UTC
 			assert today.astimezone(dates.get_timezone(tz, today)).hour != today.hour
-	
-	
+
+
 def test_utc_timestamp_to_datetime():
 	# Going from a datetime object to timezone and back should give us the same object
 	for tz in pytz.all_timezones:
 		tzinfo = dates.get_timezone(tz, test_date)
 		dt = test_date.astimezone(tzinfo)
 		assert dates.utc_timestamp_to_datetime(dt.timestamp(), tzinfo) == dt
-
+		
 		# And again with today's date
 		tzinfo = dates.get_timezone(tz, today)
 		dt = today.astimezone(tzinfo)
 		assert dates.utc_timestamp_to_datetime(dt.timestamp(), tzinfo) == dt
 
-	
+
 def test_set_timezone():
 	# Setting the timezone should change the timestamp
 	for tz in pytz.all_timezones:
@@ -79,7 +84,7 @@ def test_set_timezone():
 
 			# Difference between "today" and the new timezone should be the timezone difference
 			assert \
-				dates.set_timezone(today, dates.get_timezone(tz, today)).timestamp() +\
+				dates.set_timezone(today, dates.get_timezone(tz, today)).timestamp() + \
 				dates.get_utc_offset(tz, today).total_seconds() \
 				== today.timestamp()
 
@@ -104,6 +109,102 @@ def test_set_timezone():
 			#
 			# 		)
 			assert \
-				dates.set_timezone(test_date, dates.get_timezone(tz, test_date)).timestamp() +\
+				dates.set_timezone(test_date, dates.get_timezone(tz, test_date)).timestamp() + \
 				dates.get_utc_offset(tz, test_date).total_seconds() \
 				== test_date.timestamp()
+
+
+months = [
+		"January",
+		"February",
+		"March",
+		"April",
+		"May",
+		"June",
+		"July",
+		"August",
+		"September",
+		"October",
+		"November",
+		"December",
+		]
+
+
+def test_parse_month():
+	for month_idx, month in enumerate(months):
+		
+		month_idx += 1  # to make 1-indexed
+		
+		for i in range(3, len(month)):
+			assert dates.parse_month(month.lower()[:i]) == month
+			assert dates.parse_month(month.upper()[:i]) == month
+			assert dates.parse_month(month.capitalize()[:i]) == month
+		
+		assert dates.parse_month(month_idx) == month
+
+	for value in ["abc", 0, "0", -1, "-1", 13, "13"]:
+		with pytest.raises(ValueError):
+			dates.parse_month(value)
+
+
+def test_get_month_number():
+	for month_idx, month in enumerate(months):
+		
+		month_idx += 1  # to make 1-indexed
+		
+		for i in range(3, len(month)):
+			assert dates.get_month_number(month.lower()[:i]) == month_idx
+			assert dates.get_month_number(month.upper()[:i]) == month_idx
+			assert dates.get_month_number(month.capitalize()[:i]) == month_idx
+		
+		assert dates.get_month_number(month) == month_idx
+	
+	for month_idx in range(1, 13):
+		assert dates.get_month_number(month_idx) == month_idx
+	
+	for value in ["abc", 0, "0", -1, "-1", 13, "13"]:
+		with pytest.raises(ValueError):
+			dates.get_month_number(value)
+
+
+def test_check_date():
+	for month_idx, month in enumerate(months):
+		
+		month_idx += 1  # to make 1-indexed
+		
+		if month_idx in {9, 4, 6, 11}:
+			max_day = 30
+		elif month_idx == 2:
+			max_day = 28
+		else:
+			max_day = 31
+		
+		for day in range(-5, 36):
+			if month_idx == 2 and day == 29:
+				for i in range(3, len(month)):
+					assert dates.check_date(month.lower()[:i], 29)
+					assert dates.check_date(month.upper()[:i], 29)
+					assert dates.check_date(month.capitalize()[:i], 29)
+					
+					assert not dates.check_date(month.lower()[:i], 29, False)
+					assert not dates.check_date(month.upper()[:i], 29, False)
+					assert not dates.check_date(month.capitalize()[:i], 29, False)
+				
+				assert dates.check_date(month, 29)
+				assert not dates.check_date(month, 29, False)
+			
+			elif 0 < day <= max_day:
+				for i in range(3, len(month)):
+					assert dates.check_date(month.lower()[:i], day)
+					assert dates.check_date(month.upper()[:i], day)
+					assert dates.check_date(month.capitalize()[:i], day)
+				
+				assert dates.check_date(month, day)
+			
+			else:
+				for i in range(3, len(month)):
+					assert not dates.check_date(month.lower()[:i], day)
+					assert not dates.check_date(month.upper()[:i], day)
+					assert not dates.check_date(month.capitalize()[:i], day)
+				
+				assert not dates.check_date(month, day)