Implement duty schedule import functionality and enhance user management

- Added a new command `/import_duty_schedule` for importing duty schedules via JSON, restricted to admin users.
- Introduced a two-step import process: specifying handover time and uploading a JSON file.
- Updated the database schema to allow `telegram_user_id` to be nullable for user creation by full name.
- Implemented repository functions for user management, including `get_or_create_user_by_full_name` and `delete_duties_in_range`.
- Enhanced README documentation with details on the new import command and JSON format requirements.
- Added comprehensive tests for the duty schedule parser and integration tests for the import functionality.

tests/test_import_duty_schedule_integration.py

@@ -0,0 +1,110 @@
+"""Integration tests for duty-schedule import (parser + repo, no bot)."""
+
+from datetime import date
+
+import pytest
+
+from db import init_db
+from db.models import Base
+from db.repository import get_duties
+from db.session import get_session
+from importers.duty_schedule import DutyScheduleResult, parse_duty_schedule
+
+from handlers.import_duty_schedule import _run_import
+
+
+@pytest.fixture
+def db_url():
+    return "sqlite:///:memory:"
+
+
+@pytest.fixture(autouse=True)
+def _reset_db_session(db_url):
+    """Ensure each test uses a fresh engine for :memory: (clear global cache for test URL)."""
+    import db.session as session_module
+    session_module._engine = None
+    session_module._SessionLocal = None
+    init_db(db_url)
+    yield
+    session_module._engine = None
+    session_module._SessionLocal = None
+
+
+def test_import_creates_users_and_duties(db_url):
+    """Import creates users by full_name and correct duty records."""
+    result = DutyScheduleResult(
+        start_date=date(2026, 2, 16),
+        end_date=date(2026, 2, 18),
+        entries=[
+            ("Ivanov I.I.", [date(2026, 2, 16), date(2026, 2, 18)]),
+            ("Petrov P.P.", [date(2026, 2, 17)]),
+        ],
+    )
+    num_users, num_duties = _run_import(db_url, result, 6, 0)
+    assert num_users == 2
+    assert num_duties == 3
+
+    session = get_session(db_url)
+    try:
+        # to_date inclusive: duty on 18th has start_at 2026-02-18T06:00:00Z, so use 2026-02-19
+        duties = get_duties(session, "2026-02-16", "2026-02-19")
+    finally:
+        session.close()
+
+    assert len(duties) == 3
+    starts = {d[0].start_at for d in duties}
+    assert "2026-02-16T06:00:00Z" in starts
+    assert "2026-02-17T06:00:00Z" in starts
+    assert "2026-02-18T06:00:00Z" in starts
+
+
+def test_import_replaces_duties_in_range(db_url):
+    """Re-importing same range replaces old duties."""
+    result1 = DutyScheduleResult(
+        start_date=date(2026, 2, 16),
+        end_date=date(2026, 2, 17),
+        entries=[("Sidorov", [date(2026, 2, 16), date(2026, 2, 17)])],
+    )
+    _run_import(db_url, result1, 9, 0)
+
+    session = get_session(db_url)
+    try:
+        duties_first = get_duties(session, "2026-02-16", "2026-02-18")
+    finally:
+        session.close()
+    assert len(duties_first) == 2
+
+    result2 = DutyScheduleResult(
+        start_date=date(2026, 2, 16),
+        end_date=date(2026, 2, 17),
+        entries=[("Sidorov", [date(2026, 2, 17)])],
+    )
+    _run_import(db_url, result2, 9, 0)
+
+    session = get_session(db_url)
+    try:
+        duties_second = get_duties(session, "2026-02-16", "2026-02-18")
+    finally:
+        session.close()
+    assert len(duties_second) == 1
+    assert duties_second[0][0].start_at == "2026-02-17T09:00:00Z"
+
+
+def test_import_full_flow_parse_then_import(db_url):
+    """Parse real-looking JSON then run import."""
+    raw = (
+        '{"meta": {"start_date": "2026-02-16"}, '
+        '"schedule": [{"name": "Alexey A.", "duty": "\u0431; ; \u0432"}]}'
+    ).encode("utf-8")
+    parsed = parse_duty_schedule(raw)
+    num_users, num_duties = _run_import(db_url, parsed, 6, 0)
+    assert num_users == 1
+    assert num_duties == 2
+
+    session = get_session(db_url)
+    try:
+        duties = get_duties(session, "2026-02-16", "2026-02-19")
+    finally:
+        session.close()
+    assert len(duties) == 2
+    assert duties[0][1] == "Alexey A."