testing: Added ISO date parsing test

Added test to check the parse_iso_date function to improve
code coverage.

tests/test_timeliness.py

@@ -14,3 +14,19 @@ def test_short_month():
                      'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
     for index, s in enumerate(month_strings):
         assert timeliness.short_month('01-{:02d}-2024'.format(index + 1)) == s
+
+def test_parse_iso_date():
+    test_date_1 = timeliness.parse_iso_date("2024-01-01")
+    assert test_date_1.year==2024
+    assert test_date_1.month==1
+    assert test_date_1.day==1
+
+    test_date_2 = timeliness.parse_iso_date("2024-02-29")
+    assert test_date_2.year==2024
+    assert test_date_2.month==2
+    assert test_date_2.day==29
+
+    test_date_3 = timeliness.parse_iso_date("2024-04-01")
+    assert test_date_3.year==2024
+    assert test_date_3.month==4
+    assert test_date_3.day==1