added message for pytest.skip(); more complete docstring in _parse_delimited_date now

Author: anmyachev

pandas/_libs/tslibs/parsing.pyx

@@ -76,12 +76,16 @@ cdef inline int _parse_4digit(const char* s):
 
 cdef inline object _parse_delimited_date(object date_string, bint dayfirst):
     """
-    Parse special cases of dates: MM/DD/YYYY, DD/MM/YYYY, MM/YYYY
+    Parse special cases of dates: MM/DD/YYYY, DD/MM/YYYY, MM/YYYY.
+    At the beginning function tries to parse date in MM/DD/YYYY format, but
+    if month > 12 - in DD/MM/YYYY (`dayfirst == False`).
+    With `dayfirst == True` function makes an attempt to parse date in
+    DD/MM/YYYY, if an attemp is wrong - in DD/MM/YYYY
 
     Note
     ----
-    For MM/DD/YYYY, DD/MM/YYYY: delimiter can be a space or one of ./\-
-    For MM/YYYY: delimiter can be a space or one of /\-
+    For MM/DD/YYYY, DD/MM/YYYY: delimiter can be a space or one of ./-\\
+    For MM/YYYY: delimiter can be a space or one of /-\\
     If `date_string` can't be converted to date, then function returns
     None, None
 

pandas/tests/io/parser/test_parse_dates.py

@@ -31,6 +31,7 @@
 
 # constant
 _DEFAULT_DATETIME = datetime(1, 1, 1)
+
 # Strategy for hypothesis
 gen_random_datetime = st.dates(
     min_value=date(1900, 1, 1),  # on Windows for %y need: year > 1900
@@ -921,9 +922,8 @@ def _helper_hypothesis_delimited_date(call, date_string, **kwargs):
 ])
 def test_hypothesis_delimited_date(date_format, dayfirst, delimiter, date):
     if date_format == "%m %Y" and delimiter == ".":
-        # parse_datetime_string cannot reliably tell whether e.g. %m.%Y
-        # is a float or a date, thus we skip it
-        pytest.skip()
+        pytest.skip("parse_datetime_string cannot reliably tell whether \
+        e.g. %m.%Y is a float or a date, thus we skip it")
     result, expected = None, None
     except_in_dateutil, except_out_dateutil = None, None
     date_string = date.strftime(date_format.replace(' ', delimiter))