joplin/packages/utils/Logger.test.ts

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();
	});

});