import { describe, it, expect, jest, beforeEach, afterEach } from '@jest/globals';
import { LogLevel, Logger, logger } from './logger.js';
describe('LogLevel', () => {
it('should have correct enum values', () => {
expect(LogLevel.DEBUG).toBe(0);
expect(LogLevel.INFO).toBe(1);
expect(LogLevel.WARN).toBe(2);
expect(LogLevel.ERROR).toBe(3);
});
});
describe('Logger', () => {
let consoleErrorSpy: jest.SpiedFunction<typeof console.error>;
let mockDate: Date;
beforeEach(() => {
consoleErrorSpy = jest.spyOn(console, 'error').mockImplementation(() => {});
// Mock Date.toISOString for consistent timestamps in tests
mockDate = new Date('2023-01-01T12:00:00.000Z');
jest.spyOn(global, 'Date').mockImplementation(() => mockDate);
jest.spyOn(mockDate, 'toISOString').mockReturnValue('2023-01-01T12:00:00.000Z');
});
afterEach(() => {
jest.restoreAllMocks();
});
describe('constructor', () => {
it('should default to INFO level', () => {
const testLogger = new Logger();
expect((testLogger as any).logLevel).toBe(LogLevel.INFO);
});
it('should accept DEBUG level', () => {
const testLogger = new Logger('DEBUG');
expect((testLogger as any).logLevel).toBe(LogLevel.DEBUG);
});
it('should accept INFO level', () => {
const testLogger = new Logger('INFO');
expect((testLogger as any).logLevel).toBe(LogLevel.INFO);
});
it('should accept WARN level', () => {
const testLogger = new Logger('WARN');
expect((testLogger as any).logLevel).toBe(LogLevel.WARN);
});
it('should accept ERROR level', () => {
const testLogger = new Logger('ERROR');
expect((testLogger as any).logLevel).toBe(LogLevel.ERROR);
});
});
describe('shouldLog', () => {
it('should log messages at or above DEBUG level when set to DEBUG', () => {
const testLogger = new Logger('DEBUG');
expect((testLogger as any).shouldLog(LogLevel.DEBUG)).toBe(true);
expect((testLogger as any).shouldLog(LogLevel.INFO)).toBe(true);
expect((testLogger as any).shouldLog(LogLevel.WARN)).toBe(true);
expect((testLogger as any).shouldLog(LogLevel.ERROR)).toBe(true);
});
it('should log messages at or above INFO level when set to INFO', () => {
const testLogger = new Logger('INFO');
expect((testLogger as any).shouldLog(LogLevel.DEBUG)).toBe(false);
expect((testLogger as any).shouldLog(LogLevel.INFO)).toBe(true);
expect((testLogger as any).shouldLog(LogLevel.WARN)).toBe(true);
expect((testLogger as any).shouldLog(LogLevel.ERROR)).toBe(true);
});
it('should log messages at or above WARN level when set to WARN', () => {
const testLogger = new Logger('WARN');
expect((testLogger as any).shouldLog(LogLevel.DEBUG)).toBe(false);
expect((testLogger as any).shouldLog(LogLevel.INFO)).toBe(false);
expect((testLogger as any).shouldLog(LogLevel.WARN)).toBe(true);
expect((testLogger as any).shouldLog(LogLevel.ERROR)).toBe(true);
});
it('should log only ERROR messages when set to ERROR', () => {
const testLogger = new Logger('ERROR');
expect((testLogger as any).shouldLog(LogLevel.DEBUG)).toBe(false);
expect((testLogger as any).shouldLog(LogLevel.INFO)).toBe(false);
expect((testLogger as any).shouldLog(LogLevel.WARN)).toBe(false);
expect((testLogger as any).shouldLog(LogLevel.ERROR)).toBe(true);
});
});
describe('formatMessage', () => {
it('should format message without meta', () => {
const testLogger = new Logger();
const formatted = (testLogger as any).formatMessage('INFO', 'Test message');
expect(formatted).toBe('[2023-01-01T12:00:00.000Z] INFO: Test message');
});
it('should format message with meta object', () => {
const testLogger = new Logger();
const meta = { userId: 123, action: 'test' };
const formatted = (testLogger as any).formatMessage('ERROR', 'Test message', meta);
expect(formatted).toBe('[2023-01-01T12:00:00.000Z] ERROR: Test message {"userId":123,"action":"test"}');
});
it('should format message with primitive meta', () => {
const testLogger = new Logger();
const formatted = (testLogger as any).formatMessage('WARN', 'Test message', 'string meta');
expect(formatted).toBe('[2023-01-01T12:00:00.000Z] WARN: Test message "string meta"');
});
it('should handle null meta', () => {
const testLogger = new Logger();
const formatted = (testLogger as any).formatMessage('DEBUG', 'Test message', null);
expect(formatted).toBe('[2023-01-01T12:00:00.000Z] DEBUG: Test message');
});
});
describe('logging methods', () => {
describe('debug', () => {
it('should log debug message when level is DEBUG', () => {
const testLogger = new Logger('DEBUG');
testLogger.debug('Debug message');
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] DEBUG: Debug message');
});
it('should log debug message with meta when level is DEBUG', () => {
const testLogger = new Logger('DEBUG');
const meta = { test: 'value' };
testLogger.debug('Debug message', meta);
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] DEBUG: Debug message {"test":"value"}');
});
it('should not log debug message when level is INFO', () => {
const testLogger = new Logger('INFO');
testLogger.debug('Debug message');
expect(consoleErrorSpy).not.toHaveBeenCalled();
});
});
describe('info', () => {
it('should log info message when level is INFO', () => {
const testLogger = new Logger('INFO');
testLogger.info('Info message');
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] INFO: Info message');
});
it('should log info message with meta when level is DEBUG', () => {
const testLogger = new Logger('DEBUG');
const meta = { request: 'data' };
testLogger.info('Info message', meta);
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] INFO: Info message {"request":"data"}');
});
it('should not log info message when level is WARN', () => {
const testLogger = new Logger('WARN');
testLogger.info('Info message');
expect(consoleErrorSpy).not.toHaveBeenCalled();
});
});
describe('warn', () => {
it('should log warn message when level is WARN', () => {
const testLogger = new Logger('WARN');
testLogger.warn('Warning message');
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] WARN: Warning message');
});
it('should log warn message with meta when level is INFO', () => {
const testLogger = new Logger('INFO');
const meta = { warning: 'deprecated' };
testLogger.warn('Warning message', meta);
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] WARN: Warning message {"warning":"deprecated"}');
});
it('should not log warn message when level is ERROR', () => {
const testLogger = new Logger('ERROR');
testLogger.warn('Warning message');
expect(consoleErrorSpy).not.toHaveBeenCalled();
});
});
describe('error', () => {
it('should log error message at all levels', () => {
const levels: Array<keyof typeof LogLevel> = ['DEBUG', 'INFO', 'WARN', 'ERROR'];
levels.forEach(level => {
const testLogger = new Logger(level);
testLogger.error('Error message');
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] ERROR: Error message');
// Reset for next iteration
consoleErrorSpy.mockClear();
});
});
it('should log error message with meta', () => {
const testLogger = new Logger('ERROR');
const meta = { error: 'critical', code: 500 };
testLogger.error('Error message', meta);
expect(consoleErrorSpy).toHaveBeenCalledWith('[2023-01-01T12:00:00.000Z] ERROR: Error message {"error":"critical","code":500}');
});
});
});
describe('multiple log calls', () => {
it('should handle multiple log calls correctly', () => {
const testLogger = new Logger('DEBUG');
testLogger.debug('Debug 1');
testLogger.info('Info 1');
testLogger.warn('Warn 1');
testLogger.error('Error 1');
expect(consoleErrorSpy).toHaveBeenCalledTimes(4);
expect(consoleErrorSpy).toHaveBeenNthCalledWith(1, '[2023-01-01T12:00:00.000Z] DEBUG: Debug 1');
expect(consoleErrorSpy).toHaveBeenNthCalledWith(2, '[2023-01-01T12:00:00.000Z] INFO: Info 1');
expect(consoleErrorSpy).toHaveBeenNthCalledWith(3, '[2023-01-01T12:00:00.000Z] WARN: Warn 1');
expect(consoleErrorSpy).toHaveBeenNthCalledWith(4, '[2023-01-01T12:00:00.000Z] ERROR: Error 1');
});
});
});
describe('exported logger instance', () => {
let consoleErrorSpy: jest.SpiedFunction<typeof console.error>;
let originalEnv: string | undefined;
beforeEach(() => {
consoleErrorSpy = jest.spyOn(console, 'error').mockImplementation(() => {});
originalEnv = process.env.LOG_LEVEL;
});
afterEach(() => {
jest.restoreAllMocks();
if (originalEnv !== undefined) {
process.env.LOG_LEVEL = originalEnv;
} else {
delete process.env.LOG_LEVEL;
}
});
it('should be an instance of Logger', () => {
expect(logger).toBeInstanceOf(Logger);
});
it('should use INFO as default level when no LOG_LEVEL env var', () => {
delete process.env.LOG_LEVEL;
// Since the logger is already instantiated, we'll test its behavior
logger.info('Test info');
logger.debug('Test debug');
expect(consoleErrorSpy).toHaveBeenCalledTimes(1); // Only info should log
});
it('should respect LOG_LEVEL environment variable', () => {
// This test demonstrates the intended behavior, though the actual logger
// instance is created at module load time
expect(logger).toBeDefined();
expect(typeof logger.debug).toBe('function');
expect(typeof logger.info).toBe('function');
expect(typeof logger.warn).toBe('function');
expect(typeof logger.error).toBe('function');
});
it('should have all logging methods available', () => {
expect(typeof logger.debug).toBe('function');
expect(typeof logger.info).toBe('function');
expect(typeof logger.warn).toBe('function');
expect(typeof logger.error).toBe('function');
});
});
