feat: add datetime to string utils for lists

Author: rmkeezer

ibm_cloud_sdk_core/__init__.py

@@ -25,6 +25,8 @@
 functions:
     datetime_to_string: Serializes a datetime to a string.
     string_to_datetime: De-serializes a string to a datetime.
+    datetime_to_string_list: Serializes a list of datetimes to a list of strings.
+    string_to_datetime_list: De-serializes a list of strings to a list of datetimes.
     date_to_string: Serializes a date to a string.
     string_to_date: De-serializes a string to a date.
     convert_model: Convert a model object into an equivalent dict.
@@ -41,6 +43,7 @@
 from .cp4d_token_manager import CP4DTokenManager
 from .api_exception import ApiException
 from .utils import datetime_to_string, string_to_datetime, read_external_sources
+from .utils import datetime_to_string_list, string_to_datetime_list
 from .utils import date_to_string, string_to_date
 from .utils import convert_model, convert_list
 from .utils import get_query_param

ibm_cloud_sdk_core/utils.py

@@ -117,6 +117,40 @@ def string_to_datetime(string: str) -> datetime.datetime:
     return val.replace(tzinfo=datetime.timezone.utc)
 
 
+def string_to_datetime_list(string_list: List[str]) -> List[datetime.datetime]:
+    """De-serializes each string in a list to a datetime.
+
+    Args:
+        string_list: list of strings containing datetime in iso8601 format.
+
+    Returns:
+        the de-serialized list of strings as a list of datetime objects.
+    """
+    if not isinstance(string_list, list):
+        raise ValueError("Invalid argument type: " + str(type(string_list))
+            + ". Argument string_list must be of type List[str]")
+    datetime_list = []
+    for string_val in string_list:
+        datetime_list.append(string_to_datetime(string_val))
+    return datetime_list
+
+def datetime_to_string_list(datetime_list: List[datetime.datetime]) -> List[str]:
+    """Convert a list of datetime objects to a list of strings.
+
+    Args:
+        datetime_list: The list of datetime objects.
+
+    Returns:
+        list of datetimes serialized as strings in iso8601 format.
+    """
+    if not isinstance(datetime_list, list):
+        raise ValueError("Invalid argument type: " + str(type(datetime_list))
+            + ". Argument datetime_list must be of type List[datetime.datetime]")
+    string_list = []
+    for datetime_val in datetime_list:
+        string_list.append(datetime_to_string(datetime_val))
+    return string_list
+
 def date_to_string(val: datetime.date) -> str:
     """Convert a date object to string.
 

test/test_utils.py

@@ -21,6 +21,7 @@
 import pytest
 
 from ibm_cloud_sdk_core import string_to_datetime, datetime_to_string, get_authenticator_from_environment
+from ibm_cloud_sdk_core import string_to_datetime_list, datetime_to_string_list
 from ibm_cloud_sdk_core import string_to_date, date_to_string
 from ibm_cloud_sdk_core import convert_model, convert_list
 from ibm_cloud_sdk_core import get_query_param
@@ -116,6 +117,63 @@ def test_datetime_to_string():
     res = datetime_to_string(date)
     assert res == '2017-03-06T16:00:04.159338Z'
 
+def test_string_to_datetime_list():
+    # Assert ValueError is raised for invalid argument type
+    with pytest.raises(ValueError):
+        string_to_datetime_list(None)
+    # If the specified string does not include a timezone, it is assumed to be UTC
+    date_list = string_to_datetime_list([ '2017-03-06 16:00:04.159338' ])
+    assert date_list[0].day == 6
+    assert date_list[0].hour == 16
+    assert date_list[0].tzinfo.utcoffset(None) == datetime.timezone.utc.utcoffset(None)
+    # Test date string with TZ specified as '+xxxx'
+    date_list = string_to_datetime_list([ '2017-03-06 16:00:04.159338+0600' ])
+    assert date_list[0].day == 6
+    assert date_list[0].hour == 16
+    assert date_list[0].tzinfo.utcoffset(None).total_seconds() == 6 * 60 * 60
+    # Test date string with TZ specified as 'Z'
+    date_list = string_to_datetime_list([ '2017-03-06 16:00:04.159338Z' ])
+    assert date_list[0].day == 6
+    assert date_list[0].hour == 16
+    assert date_list[0].tzinfo.utcoffset(None) == datetime.timezone.utc.utcoffset(None)
+    # Test multiple datetimes in a list
+    date_list = string_to_datetime_list([ '2017-03-06 16:00:04.159338', '2017-03-07 17:00:04.159338' ])
+    assert date_list[0].day == 6
+    assert date_list[0].hour == 16
+    assert date_list[0].tzinfo.utcoffset(None) == datetime.timezone.utc.utcoffset(None)
+    assert date_list[1].day == 7
+    assert date_list[1].hour == 17
+    assert date_list[1].tzinfo.utcoffset(None) == datetime.timezone.utc.utcoffset(None)
+
+
+def test_datetime_to_string_list():
+    # Assert ValueError is raised for invalid argument type
+    with pytest.raises(ValueError):
+        datetime_to_string_list(None)
+    # If specified datetime list item is None, return list of None
+    assert datetime_to_string_list([None]) == [None]
+    # If specified datetime list is empty, return empty list
+    assert datetime_to_string_list([]) == []
+    # If the specified date list item is "naive", it is interpreted as a UTC date
+    date_list = [ datetime.datetime(2017, 3, 6, 16, 0, 4, 159338) ]
+    res = datetime_to_string_list(date_list)
+    assert res == [ '2017-03-06T16:00:04.159338Z' ]
+    # Test date list item with UTC timezone
+    date_list = [ datetime.datetime(2017, 3, 6, 16, 0, 4, 159338,
+                             datetime.timezone.utc) ]
+    res = datetime_to_string_list(date_list)
+    assert res == [ '2017-03-06T16:00:04.159338Z' ]
+    # Test date list item with non-UTC timezone
+    tzn = datetime.timezone(datetime.timedelta(hours=-6))
+    date_list = [ datetime.datetime(2017, 3, 6, 10, 0, 4, 159338, tzn) ]
+    res = datetime_to_string_list(date_list)
+    assert res == [ '2017-03-06T16:00:04.159338Z' ]
+    # Test specified date list with multiple items
+    date_list = [ datetime.datetime(2017, 3, 6, 16, 0, 4, 159338),
+                  datetime.datetime(2017, 3, 6, 16, 0, 4, 159338,
+                        datetime.timezone.utc) ]
+    res = datetime_to_string_list(date_list)
+    assert res == [ '2017-03-06T16:00:04.159338Z', '2017-03-06T16:00:04.159338Z' ]
 
 def test_date_conversion():
     date = string_to_date('2017-03-06')