paper-dynasty-gameplay-webapp/tests/demo_data_isolation.py

"""
Demonstration of data isolation in tests.

This shows how our test infrastructure prevents data interference between tests.
"""
import pytest
from sqlmodel import select

from app.models.player import Player
from tests.factories.player_factory import PlayerFactory


class TestDataIsolationDemo:
    """Demonstrate how data isolation works between tests."""

    def test_first_creates_player(self, db_session):
        """First test creates a player - this data should not affect other tests."""
        # Create player with specific name
        player = PlayerFactory.create(db_session, name="Test Player Alpha", cost=100)

        # Verify it exists in this test's transaction
        result = db_session.exec(select(Player).where(Player.name == "Test Player Alpha")).first()
        assert result is not None
        assert result.cost == 100

        print(f"Created player with ID: {player.id} in first test")

    def test_second_cannot_see_first_player(self, db_session):
        """Second test runs in separate transaction - cannot see first test's data."""
        # Try to find the player from the first test
        result = db_session.exec(select(Player).where(Player.name == "Test Player Alpha")).first()

        # Should be None because first test's transaction was rolled back
        assert result is None

        # Create our own player with same name but different cost
        player = PlayerFactory.create(db_session, name="Test Player Alpha", cost=200)
        assert player.cost == 200

        print(f"Cannot see first test's player - created new one with ID: {player.id}")

    def test_third_also_isolated(self, db_session):
        """Third test is also completely isolated from previous tests."""
        # Should not see players from either previous test
        results = db_session.exec(select(Player).where(Player.name == "Test Player Alpha")).all()
        assert len(results) == 0

        # Can create multiple players without conflict
        player1 = PlayerFactory.create(db_session, name="Test Player Alpha", cost=300)
        player2 = PlayerFactory.create(db_session, name="Test Player Beta", cost=400)

        # Both exist in this test's transaction
        all_results = db_session.exec(select(Player)).all()
        assert len(all_results) == 2

        print(f"Third test: created players with IDs {player1.id} and {player2.id}")


class TestDataIsolationWithFreshSession:
    """Demonstrate fresh_db_session behavior (real commits)."""

    def test_with_fresh_session_persists_data(self, fresh_db_session):
        """Test using fresh_db_session - data actually commits to test database."""
        # Create player with real commit
        player = PlayerFactory.create(fresh_db_session, name="Persistent Player", cost=500)
        fresh_db_session.commit()  # Real commit to test database

        # Verify it's committed
        fresh_db_session.refresh(player)
        assert player.id is not None

        print(f"Committed player with ID: {player.id} to test database")

        # Manual cleanup for this demonstration
        fresh_db_session.delete(player)
        fresh_db_session.commit()
        print("Manually cleaned up persistent player")

    def test_after_fresh_session_cleanup(self, db_session):
        """This test should not see the fresh session data (it was cleaned up)."""
        result = db_session.exec(select(Player).where(Player.name == "Persistent Player")).first()
        assert result is None
        print("Confirmed: Fresh session data was properly cleaned up")


class TestDataIsolationFactories:
    """Demonstrate how factories prevent ID conflicts."""

    def test_factory_generates_unique_ids(self, db_session):
        """Factories generate unique IDs to prevent conflicts."""
        # Create multiple players - factories ensure unique IDs
        players = [
            PlayerFactory.create(db_session, name=f"Player {i}")
            for i in range(5)
        ]

        # All should have different IDs
        player_ids = [p.id for p in players]
        assert len(set(player_ids)) == 5  # All unique

        print(f"Generated unique IDs: {player_ids}")

    def test_can_create_same_names_different_ids(self, db_session):
        """Different tests can create objects with same names but different IDs."""
        # This won't conflict with previous test because transaction is isolated
        players = [
            PlayerFactory.create(db_session, name="Player 1"),
            PlayerFactory.create(db_session, name="Player 2"),
        ]

        # IDs will be different from previous test
        print(f"Same names, different IDs: {[p.id for p in players]}")

        # Names can be the same across tests, IDs will always be unique
        assert players[0].name == "Player 1"
        assert players[1].name == "Player 2"