refactor(MQTT Node): Refactor, fix duplicate triggers, and add Unit tests (#9847)

Co-authored-by: Elias Meire <elias@meire.dev>

packages/nodes-base/nodes/MQTT/test/MqttTrigger.node.test.ts

@@ -0,0 +1,123 @@
+import type { MqttClient, OnMessageCallback } from 'mqtt';
+import { returnJsonArray } from 'n8n-core';
+import { captor, mock } from 'jest-mock-extended';
+import type { ICredentialDataDecryptedObject, ITriggerFunctions } from 'n8n-workflow';
+
+import { MqttTrigger } from '../MqttTrigger.node';
+import { createClient } from '../GenericFunctions';
+
+jest.mock('../GenericFunctions', () => {
+	const mockMqttClient = mock<MqttClient>();
+	return {
+		createClient: jest.fn().mockResolvedValue(mockMqttClient),
+	};
+});
+
+describe('MQTT Trigger Node', () => {
+	const topic = 'test/topic';
+	const payload = Buffer.from('{"testing": true}');
+	const credentials = mock<ICredentialDataDecryptedObject>();
+	const triggerFunctions = mock<ITriggerFunctions>({
+		helpers: { returnJsonArray },
+	});
+
+	beforeEach(() => {
+		jest.clearAllMocks();
+
+		triggerFunctions.getCredentials.calledWith('mqtt').mockResolvedValue(credentials);
+		triggerFunctions.getNodeParameter.calledWith('topics').mockReturnValue(topic);
+	});
+
+	it('should emit in manual mode', async () => {
+		triggerFunctions.getMode.mockReturnValue('manual');
+		triggerFunctions.getNodeParameter.calledWith('options').mockReturnValue({});
+
+		const response = await new MqttTrigger().trigger.call(triggerFunctions);
+		expect(response.manualTriggerFunction).toBeDefined();
+		expect(response.closeFunction).toBeDefined();
+
+		expect(triggerFunctions.getCredentials).toHaveBeenCalledTimes(1);
+		expect(triggerFunctions.getNodeParameter).toHaveBeenCalledTimes(2);
+
+		// manually trigger the node, like Workflow.runNode does
+		const triggerPromise = response.manualTriggerFunction!();
+
+		const mockMqttClient = await createClient(mock());
+		expect(mockMqttClient.on).not.toHaveBeenCalled();
+
+		const onMessageCaptor = captor<OnMessageCallback>();
+		expect(mockMqttClient.once).toHaveBeenCalledWith('message', onMessageCaptor);
+		expect(mockMqttClient.subscribeAsync).toHaveBeenCalledWith({ [topic]: { qos: 0 } });
+		expect(triggerFunctions.emit).not.toHaveBeenCalled();
+
+		// simulate a message
+		const onMessage = onMessageCaptor.value;
+		onMessage('test/topic', payload, mock());
+		expect(triggerFunctions.emit).toHaveBeenCalledWith([
+			[{ json: { message: '{"testing": true}', topic } }],
+		]);
+
+		// wait for the promise to resolve
+		await new Promise((resolve) => setImmediate(resolve));
+		await expect(triggerPromise).resolves.toEqual(undefined);
+
+		expect(mockMqttClient.endAsync).not.toHaveBeenCalled();
+		await response.closeFunction!();
+		expect(mockMqttClient.endAsync).toHaveBeenCalledTimes(1);
+	});
+
+	it('should emit in trigger mode', async () => {
+		triggerFunctions.getMode.mockReturnValue('trigger');
+		triggerFunctions.getNodeParameter.calledWith('options').mockReturnValue({});
+
+		const response = await new MqttTrigger().trigger.call(triggerFunctions);
+		expect(response.manualTriggerFunction).toBeDefined();
+		expect(response.closeFunction).toBeDefined();
+
+		expect(triggerFunctions.getCredentials).toHaveBeenCalledTimes(1);
+		expect(triggerFunctions.getNodeParameter).toHaveBeenCalledTimes(2);
+
+		const mockMqttClient = await createClient(mock());
+		expect(mockMqttClient.once).not.toHaveBeenCalled();
+
+		const onMessageCaptor = captor<OnMessageCallback>();
+		expect(mockMqttClient.on).toHaveBeenCalledWith('message', onMessageCaptor);
+		expect(mockMqttClient.subscribeAsync).toHaveBeenCalledWith({ [topic]: { qos: 0 } });
+		expect(triggerFunctions.emit).not.toHaveBeenCalled();
+
+		// simulate a message
+		const onMessage = onMessageCaptor.value;
+		onMessage('test/topic', payload, mock());
+		expect(triggerFunctions.emit).toHaveBeenCalledWith(
+			[[{ json: { message: '{"testing": true}', topic } }]],
+			undefined,
+			undefined,
+		);
+
+		expect(mockMqttClient.endAsync).not.toHaveBeenCalled();
+		await response.closeFunction!();
+		expect(mockMqttClient.endAsync).toHaveBeenCalledTimes(1);
+	});
+
+	it('should parse JSON messages when configured', async () => {
+		triggerFunctions.getMode.mockReturnValue('trigger');
+		triggerFunctions.getNodeParameter.calledWith('options').mockReturnValue({
+			jsonParseBody: true,
+		});
+
+		await new MqttTrigger().trigger.call(triggerFunctions);
+
+		const mockMqttClient = await createClient(mock());
+		const onMessageCaptor = captor<OnMessageCallback>();
+		expect(mockMqttClient.on).toHaveBeenCalledWith('message', onMessageCaptor);
+
+		// simulate a message
+		const onMessage = onMessageCaptor.value;
+		onMessage('test/topic', payload, mock());
+		expect(triggerFunctions.emit).toHaveBeenCalledWith(
+			[[{ json: { message: { testing: true }, topic } }]],
+			undefined,
+			undefined,
+		);
+	});
+});