import pytest
from models import Ticket, Track

def test_ticket_instantiation():
    """
    Verifies that a Ticket can be instantiated with its required fields:
    id, description, status, assigned_to.
    """
    ticket_id = "T1"
    description = "Implement surgical code changes"
    status = "todo"
    assigned_to = "tier3-worker"
    
    ticket = Ticket(
        id=ticket_id,
        description=description,
        status=status,
        assigned_to=assigned_to
    )
    
    assert ticket.id == ticket_id
    assert ticket.description == description
    assert ticket.status == status
    assert ticket.assigned_to == assigned_to
    assert ticket.depends_on == []

def test_ticket_with_dependencies():
    """
    Verifies that a Ticket can store dependencies.
    """
    ticket = Ticket(
        id="T2",
        description="Write code",
        status="todo",
        assigned_to="worker-1",
        depends_on=["T1"]
    )
    assert ticket.depends_on == ["T1"]

def test_track_instantiation():
    """
    Verifies that a Track can be instantiated with its required fields:
    id, description, and a list of Tickets.
    """
    ticket1 = Ticket(id="T1", description="Task 1", status="todo", assigned_to="a")
    ticket2 = Ticket(id="T2", description="Task 2", status="todo", assigned_to="b")
    
    track_id = "TRACK-1"
    track_desc = "Implement MMA Models"
    tickets = [ticket1, ticket2]
    
    track = Track(
        id=track_id,
        description=track_desc,
        tickets=tickets
    )
    
    assert track.id == track_id
    assert track.description == track_desc
    assert len(track.tickets) == 2
    assert track.tickets[0].id == "T1"
    assert track.tickets[1].id == "T2"

def test_track_can_handle_empty_tickets():
    """
    Verifies that a Track can be instantiated with an empty list of tickets.
    """
    track = Track(id="TRACK-2", description="Empty Track", tickets=[])
    assert track.tickets == []