feat: add trusted groups functionality for duty information

- Introduced a new `trusted_groups` table to store groups authorized to receive duty information.
- Implemented functions to add, remove, and check trusted groups in the database.
- Enhanced command handlers to manage trusted groups, including `/trust_group` and `/untrust_group` commands for admin users.
- Updated internationalization messages to support new commands and group status notifications.
- Added unit tests for trusted groups repository functions to ensure correct behavior and data integrity.

tests/test_trusted_groups_repository.py

@@ -0,0 +1,84 @@
+"""Unit tests for trusted_groups repository functions."""
+
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from duty_teller.db.models import Base
+from duty_teller.db.repository import (
+    is_trusted_group,
+    add_trusted_group,
+    remove_trusted_group,
+    get_all_trusted_group_ids,
+)
+
+
+@pytest.fixture
+def session():
+    """In-memory SQLite session with all tables (including trusted_groups)."""
+    engine = create_engine(
+        "sqlite:///:memory:", connect_args={"check_same_thread": False}
+    )
+    Base.metadata.create_all(engine)
+    Session = sessionmaker(bind=engine, autocommit=False, autoflush=False)
+    s = Session()
+    try:
+        yield s
+    finally:
+        s.close()
+        engine.dispose()
+
+
+def test_is_trusted_group_empty_returns_false(session):
+    """is_trusted_group returns False when no record exists."""
+    assert is_trusted_group(session, 100) is False
+    assert is_trusted_group(session, 200) is False
+
+
+def test_add_trusted_group_creates_record(session):
+    """add_trusted_group creates a record and returns TrustedGroup."""
+    record = add_trusted_group(session, 100, added_by_user_id=12345)
+    assert record.chat_id == 100
+    assert record.added_by_user_id == 12345
+    assert record.added_at is not None
+
+
+def test_is_trusted_group_after_add_returns_true(session):
+    """is_trusted_group returns True after add_trusted_group."""
+    add_trusted_group(session, 100)
+    assert is_trusted_group(session, 100) is True
+    assert is_trusted_group(session, 101) is False
+
+
+def test_add_trusted_group_without_added_by_user_id(session):
+    """add_trusted_group accepts added_by_user_id None."""
+    record = add_trusted_group(session, 200, added_by_user_id=None)
+    assert record.chat_id == 200
+    assert record.added_by_user_id is None
+
+
+def test_remove_trusted_group_removes_record(session):
+    """remove_trusted_group removes the record."""
+    add_trusted_group(session, 100)
+    assert is_trusted_group(session, 100) is True
+    remove_trusted_group(session, 100)
+    assert is_trusted_group(session, 100) is False
+
+
+def test_remove_trusted_group_idempotent(session):
+    """remove_trusted_group on non-existent chat_id does not raise."""
+    remove_trusted_group(session, 999)
+
+
+def test_get_all_trusted_group_ids_empty(session):
+    """get_all_trusted_group_ids returns empty list when no trusted groups."""
+    assert get_all_trusted_group_ids(session) == []
+
+
+def test_get_all_trusted_group_ids_returns_added_chats(session):
+    """get_all_trusted_group_ids returns all trusted chat_ids."""
+    add_trusted_group(session, 10)
+    add_trusted_group(session, 20)
+    add_trusted_group(session, 30)
+    ids = get_all_trusted_group_ids(session)
+    assert set(ids) == {10, 20, 30}