import { Logger, LogLevel, getCorrelationId, generateCorrelationId } from '../src/logger';
describe('logger', () => {
const originalEnv = process.env;
const originalConsoleLog = console.log;
const originalConsoleError = console.error;
const originalConsoleWarn = console.warn;
const originalConsoleDebug = console.debug;
let logOutput: string[] = [];
let errorOutput: string[] = [];
let warnOutput: string[] = [];
let debugOutput: string[] = [];
beforeEach(() => {
logOutput = [];
errorOutput = [];
warnOutput = [];
debugOutput = [];
process.env = { ...originalEnv };
console.log = (...args: unknown[]) => {
logOutput.push(args.map(String).join(' '));
};
console.error = (...args: unknown[]) => {
errorOutput.push(args.map(String).join(' '));
};
console.warn = (...args: unknown[]) => {
warnOutput.push(args.map(String).join(' '));
};
console.debug = (...args: unknown[]) => {
debugOutput.push(args.map(String).join(' '));
};
});
afterEach(() => {
process.env = originalEnv;
console.log = originalConsoleLog;
console.error = originalConsoleError;
console.warn = originalConsoleWarn;
console.debug = originalConsoleDebug;
});
describe('LogLevel', () => {
it('has correct enum values', () => {
expect(LogLevel.DEBUG).toBe('DEBUG');
expect(LogLevel.INFO).toBe('INFO');
expect(LogLevel.WARN).toBe('WARN');
expect(LogLevel.ERROR).toBe('ERROR');
});
});
describe('generateCorrelationId', () => {
it('generates unique IDs', () => {
const id1 = generateCorrelationId();
const id2 = generateCorrelationId();
expect(id1).toBeTruthy();
expect(id2).toBeTruthy();
expect(id1).not.toBe(id2);
expect(id1.length).toBeGreaterThan(0);
});
it('generates IDs with expected format', () => {
const id = generateCorrelationId();
expect(typeof id).toBe('string');
expect(id.length).toBeGreaterThan(10);
});
});
describe('getCorrelationId', () => {
it('extracts correlation ID from headers', () => {
const req = {
headers: {
'x-correlation-id': 'test-correlation-123',
},
} as never;
const id = getCorrelationId(req);
expect(id).toBe('test-correlation-123');
});
it('extracts correlation ID from headers case-insensitive', () => {
const req = {
headers: {
'X-Correlation-ID': 'test-correlation-456',
},
} as never;
const id = getCorrelationId(req);
expect(id).toBe('test-correlation-456');
});
it('generates new ID if not in headers', () => {
const req = {
headers: {},
} as never;
const id = getCorrelationId(req);
expect(id).toBeTruthy();
expect(typeof id).toBe('string');
});
it('generates new ID if header is empty', () => {
const req = {
headers: {
'x-correlation-id': '',
},
} as never;
const id = getCorrelationId(req);
expect(id).toBeTruthy();
expect(id).not.toBe('');
});
});
describe('Logger', () => {
it('creates logger with default INFO level', () => {
delete process.env.MCP_LOG_LEVEL;
const logger = new Logger();
expect(logger.getLevel()).toBe(LogLevel.INFO);
});
it('creates logger with level from env', () => {
process.env.MCP_LOG_LEVEL = 'DEBUG';
const logger = new Logger();
expect(logger.getLevel()).toBe(LogLevel.DEBUG);
});
it('creates logger with level from env (case-insensitive)', () => {
process.env.MCP_LOG_LEVEL = 'error';
const logger = new Logger();
expect(logger.getLevel()).toBe(LogLevel.ERROR);
});
it('defaults to INFO for invalid level', () => {
process.env.MCP_LOG_LEVEL = 'INVALID';
const logger = new Logger();
expect(logger.getLevel()).toBe(LogLevel.INFO);
});
it('logs DEBUG messages when level is DEBUG', () => {
process.env.MCP_LOG_LEVEL = 'DEBUG';
const logger = new Logger();
logger.debug('test-id', 'Debug message');
expect(debugOutput.length).toBeGreaterThan(0);
expect(debugOutput[0]).toContain('[test-id]');
expect(debugOutput[0]).toContain('DEBUG');
expect(debugOutput[0]).toContain('Debug message');
});
it('does not log DEBUG messages when level is INFO', () => {
process.env.MCP_LOG_LEVEL = 'INFO';
const logger = new Logger();
logger.debug('test-id', 'Debug message');
expect(debugOutput.length).toBe(0);
});
it('logs INFO messages when level is INFO', () => {
process.env.MCP_LOG_LEVEL = 'INFO';
const logger = new Logger();
logger.info('test-id', 'Info message');
expect(logOutput.length).toBeGreaterThan(0);
expect(logOutput[0]).toContain('[test-id]');
expect(logOutput[0]).toContain('INFO');
expect(logOutput[0]).toContain('Info message');
});
it('logs INFO messages when level is DEBUG', () => {
process.env.MCP_LOG_LEVEL = 'DEBUG';
const logger = new Logger();
logger.info('test-id', 'Info message');
expect(logOutput.length).toBeGreaterThan(0);
});
it('does not log INFO messages when level is WARN', () => {
process.env.MCP_LOG_LEVEL = 'WARN';
const logger = new Logger();
logger.info('test-id', 'Info message');
expect(logOutput.length).toBe(0);
});
it('logs WARN messages when level is WARN', () => {
process.env.MCP_LOG_LEVEL = 'WARN';
const logger = new Logger();
logger.warn('test-id', 'Warning message');
expect(warnOutput.length).toBeGreaterThan(0);
expect(warnOutput[0]).toContain('[test-id]');
expect(warnOutput[0]).toContain('WARN');
expect(warnOutput[0]).toContain('Warning message');
});
it('does not log WARN messages when level is ERROR', () => {
process.env.MCP_LOG_LEVEL = 'ERROR';
const logger = new Logger();
logger.warn('test-id', 'Warning message');
expect(warnOutput.length).toBe(0);
});
it('logs ERROR messages', () => {
process.env.MCP_LOG_LEVEL = 'ERROR';
const logger = new Logger();
logger.error('test-id', 'Error message');
expect(errorOutput.length).toBeGreaterThan(0);
expect(errorOutput[0]).toContain('[test-id]');
expect(errorOutput[0]).toContain('ERROR');
expect(errorOutput[0]).toContain('Error message');
});
it('logs ERROR messages at any level', () => {
process.env.MCP_LOG_LEVEL = 'DEBUG';
const logger = new Logger();
logger.error('test-id', 'Error message');
expect(errorOutput.length).toBeGreaterThan(0);
});
it('includes error object in ERROR log', () => {
process.env.MCP_LOG_LEVEL = 'ERROR';
const logger = new Logger();
const err = new Error('Test error');
logger.error('test-id', 'Error occurred', err);
expect(errorOutput.length).toBeGreaterThan(0);
expect(errorOutput[0]).toContain('[test-id]');
expect(errorOutput[0]).toContain('Error occurred');
});
it('formats log message correctly', () => {
process.env.MCP_LOG_LEVEL = 'INFO';
const logger = new Logger();
logger.info('corr-123', 'Test message');
expect(logOutput[0]).toMatch(/\[corr-123\]\s+INFO\s+Test message/);
});
});
});
