test(core): Add integration test for JS task runner (#12804)

Co-authored-by: Iván Ovejero <ivov.src@gmail.com>

packages/cli/test/integration/task-runners/task-runner-module.internal.test.ts

@@ -0,0 +1,41 @@
+import { TaskRunnersConfig } from '@n8n/config';
+import { Container } from '@n8n/di';
+
+import { TaskRunnerModule } from '@/task-runners/task-runner-module';
+
+import { InternalTaskRunnerDisconnectAnalyzer } from '../../../src/task-runners/internal-task-runner-disconnect-analyzer';
+import { TaskRunnerWsServer } from '../../../src/task-runners/task-runner-ws-server';
+
+describe('TaskRunnerModule in internal mode', () => {
+	const runnerConfig = Container.get(TaskRunnersConfig);
+	runnerConfig.port = 0; // Random port
+	runnerConfig.mode = 'internal';
+	runnerConfig.enabled = true;
+	const module = Container.get(TaskRunnerModule);
+
+	afterEach(async () => {
+		await module.stop();
+	});
+
+	describe('start', () => {
+		it('should throw if the task runner is disabled', async () => {
+			runnerConfig.enabled = false;
+
+			// Act
+			await expect(module.start()).rejects.toThrow('Task runner is disabled');
+		});
+
+		it('should start the task runner', async () => {
+			runnerConfig.enabled = true;
+
+			// Act
+			await module.start();
+		});
+
+		it('should use InternalTaskRunnerDisconnectAnalyzer', () => {
+			const wsServer = Container.get(TaskRunnerWsServer);
+
+			expect(wsServer.getDisconnectAnalyzer()).toBeInstanceOf(InternalTaskRunnerDisconnectAnalyzer);
+		});
+	});
+});