Desktop, Cli: Improved log formatting and allow saving last lines of log to memory

packages/utils/Logger.test.ts

@@ -0,0 +1,89 @@
+import Logger, { LogLevel, TargetType } from './Logger';
+import { WriteFileOptions, appendFile, mkdirp, readFile, remove } from 'fs-extra';
+
+Logger.fsDriver_ = {
+	appendFile: async (path, content, encoding) => {
+		return await appendFile(path, content, encoding as WriteFileOptions);
+	},
+};
+
+const testDirPath = `${__dirname}/LoggerTests`;
+
+const logPath = () => {
+	return `${testDirPath}/log.txt`;
+};
+
+const getLogContent = async () => {
+	return readFile(logPath(), 'utf-8');
+};
+
+const createLogger = () => {
+	const logger = new Logger();
+	logger.addTarget(TargetType.File, {
+		prefix: 'testing',
+		path: logPath(),
+		level: LogLevel.Debug,
+	});
+	return logger;
+};
+
+describe('Logger', () => {
+
+	beforeEach(async () => {
+		await mkdirp(testDirPath);
+	});
+
+	afterEach(async () => {
+		await remove(testDirPath);
+	});
+
+	it('should log to file', async () => {
+		jest.useFakeTimers().setSystemTime(new Date('2020-01-01'));
+
+		const logger = createLogger();
+		logger.debug('one');
+		logger.warn('two');
+		logger.error('three');
+
+		await logger.waitForFileWritesToComplete_();
+
+		expect(await getLogContent()).toBe([
+			'2020-01-01 00:00:00: testing: one',
+			'2020-01-01 00:00:00: testing: [warn] two',
+			'2020-01-01 00:00:00: testing: [error] three',
+			'',
+		].join('\n'));
+
+		// Shouldn't have kept any line, since keptLineCount was not set
+		expect(logger.keptLines).toEqual([]);
+
+		jest.useRealTimers();
+	});
+
+	it('should keep the last lines', async () => {
+		jest.useFakeTimers().setSystemTime(new Date('2020-01-01'));
+
+		const logger = createLogger();
+		logger.keptLineCount = 2;
+		logger.info('one');
+		logger.info('two');
+		logger.info('three');
+
+		await logger.waitForFileWritesToComplete_();
+
+		expect(await getLogContent()).toBe([
+			'2020-01-01 00:00:00: testing: one',
+			'2020-01-01 00:00:00: testing: two',
+			'2020-01-01 00:00:00: testing: three',
+			'',
+		].join('\n'));
+
+		expect(logger.keptLines).toEqual([
+			'2020-01-01 00:00:00: testing: two',
+			'2020-01-01 00:00:00: testing: three',
+		]);
+
+		jest.useRealTimers();
+	});
+
+});