Fix nothing logged in frontend when log_level warn is set. https://github.com/Koenkk/zigbee2mqtt/issues/5812

test/logger.test.js

@@ -6,6 +6,7 @@ const path = require('path');
 const data = require('./stub/data');
 let stdOutWriteOriginal;
 const rimraf = require('rimraf');
+const Transport = require('winston-transport');
 
 describe('Logger', () => {
     beforeEach(async () => {
@@ -66,6 +67,18 @@ describe('Logger', () => {
         expect(logger.getLevel()).toBe('debug');
     });
 
+    it('Add transport', () => {
+        class DummyTransport extends Transport {
+            log(info, callback) {
+            }
+        }
+
+        const logger = require('../lib/util/logger.js');
+        expect(logger.transports.length).toBe(2);
+        logger.addTransport(new DummyTransport());
+        expect(logger.transports.length).toBe(3);
+    });
+
     it('Set and get log level warn <-> warning', () => {
         const logger = require('../lib/util/logger.js');
         logger.logOutput();

test/stub/logger.js

@@ -19,6 +19,7 @@ const mock = {
     cleanup: jest.fn(),
     logOutput: jest.fn(),
     add: (transport) => transports.push(transport),
+    addTransport: (transport) => transports.push(transport),
     setLevel: (newLevel) => {level = newLevel},
     getLevel: () => level,
     setTransportsEnabled: (value) => {transportsEnabled = value},