refactor(core): Centralize CronJob management (#10033)

packages/core/test/ScheduledTaskManager.test.ts

@@ -0,0 +1,54 @@
+import type { Workflow } from 'n8n-workflow';
+import { mock } from 'jest-mock-extended';
+
+import { ScheduledTaskManager } from '@/ScheduledTaskManager';
+
+describe('ScheduledTaskManager', () => {
+	const workflow = mock<Workflow>({ timezone: 'GMT' });
+	const everyMinute = '0 * * * * *';
+	const onTick = jest.fn();
+
+	let scheduledTaskManager: ScheduledTaskManager;
+
+	beforeEach(() => {
+		jest.clearAllMocks();
+		jest.useFakeTimers();
+		scheduledTaskManager = new ScheduledTaskManager();
+	});
+
+	it('should throw when workflow timezone is invalid', () => {
+		expect(() =>
+			scheduledTaskManager.registerCron(
+				mock<Workflow>({ timezone: 'somewhere' }),
+				everyMinute,
+				onTick,
+			),
+		).toThrow('Invalid timezone.');
+	});
+
+	it('should throw when cron expression is invalid', () => {
+		expect(() =>
+			//@ts-expect-error invalid cron expression is a type-error
+			scheduledTaskManager.registerCron(workflow, 'invalid-cron-expression', onTick),
+		).toThrow();
+	});
+
+	it('should register valid CronJobs', async () => {
+		scheduledTaskManager.registerCron(workflow, everyMinute, onTick);
+
+		expect(onTick).not.toHaveBeenCalled();
+		jest.advanceTimersByTime(10 * 60 * 1000); // 10 minutes
+		expect(onTick).toHaveBeenCalledTimes(10);
+	});
+
+	it('should deregister CronJobs for a workflow', async () => {
+		scheduledTaskManager.registerCron(workflow, everyMinute, onTick);
+		scheduledTaskManager.registerCron(workflow, everyMinute, onTick);
+		scheduledTaskManager.registerCron(workflow, everyMinute, onTick);
+		scheduledTaskManager.deregisterCrons(workflow.id);
+
+		expect(onTick).not.toHaveBeenCalled();
+		jest.advanceTimersByTime(10 * 60 * 1000); // 10 minutes
+		expect(onTick).not.toHaveBeenCalled();
+	});
+});