feat: implement crontab manager for managing alarms

tests/test_crontab.py

@@ -0,0 +1,63 @@
+import pytest
+import tempfile
+import uuid
+from api.crontab_manager import CrontabManager
+
+@pytest.fixture
+def crontab_file():
+    with tempfile.NamedTemporaryFile(mode='w+', delete=False) as f:
+        pass
+    yield f.name
+
+def test_crontab_manager_empty(crontab_file):
+    manager = CrontabManager(tabfile=crontab_file)
+    assert manager.get_alarms() == []
+
+def test_add_and_list_alarm(crontab_file):
+    manager = CrontabManager(tabfile=crontab_file)
+    alarm_id = str(uuid.uuid4())
+    manager.set_alarm(
+        alarm_id=alarm_id,
+        cron_expression="30 7 * * *",
+        command="python wecker.py",
+        is_enabled=True
+    )
+    
+    alarms = manager.get_alarms()
+    assert len(alarms) == 1
+    assert alarms[0]["id"] == alarm_id
+    assert alarms[0]["cron_expression"] == "30 7 * * *"
+    assert alarms[0]["command"] == "python wecker.py"
+    assert alarms[0]["is_enabled"] is True
+
+def test_update_alarm(crontab_file):
+    manager = CrontabManager(tabfile=crontab_file)
+    alarm_id = "test-id"
+    manager.set_alarm(
+        alarm_id=alarm_id,
+        cron_expression="30 7 * * *",
+        command="python wecker.py",
+        is_enabled=True
+    )
+    
+    manager.set_alarm(
+        alarm_id=alarm_id,
+        cron_expression="0 8 * * *",
+        command="python wecker.py --loud",
+        is_enabled=False
+    )
+    
+    alarms = manager.get_alarms()
+    assert len(alarms) == 1
+    assert alarms[0]["cron_expression"] == "0 8 * * *"
+    assert alarms[0]["command"] == "python wecker.py --loud"
+    assert alarms[0]["is_enabled"] is False
+
+def test_delete_alarm(crontab_file):
+    manager = CrontabManager(tabfile=crontab_file)
+    alarm_id = "test-id-2"
+    manager.set_alarm(alarm_id, "0 0 * * *", "cmd", True)
+    assert len(manager.get_alarms()) == 1
+    
+    manager.delete_alarm(alarm_id)
+    assert len(manager.get_alarms()) == 0