some functions were changed in odoo 11.

Addons: resource/models/resource.py

Odoo 10: get_working_intervals_of_day

Odoo 11: i think:

@api.multi
def _get_day_work_intervals(self, day_date, start_time=None, end_time=None, compute_leaves=False, resource_id=None):

https://github.com/OCA/crm/blob/10.0/calendar_resource/models/calendar_event.py#L226

datetime_start = datetime.combine(day, time(00, 00, 00))
datetime_end = datetime.combine(day, time(23, 59, 59))

intervals = \
    resource.calendar_id.get_working_intervals_of_day(
    start_dt=datetime_start,
    end_dt=datetime_end,
    resource_id=resource.id,
)

change to

datetime_start = datetime.combine(day, time(00, 00, 00))
datetime_end = datetime.combine(day, time(23, 59, 59))

st = time(00, 00, 00)
et = time(23, 59, 59)

intervals = \
    resource.calendar_id.get_working_intervals_of_day(
    day_date = date,
    start_dt= st,
    end_dt= et,
    resource_id=resource.id,
)

In odoo 10 Working Time is not defaultbut odoo 11 sets default.

https://github.com/odoo/odoo/blob/11.0/addons/resource/models/resource.py#L655-L715

Line 664, 682, 700, 715