logger.test.ts

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { createLogger, LogLevel, setLogLevel, addTransport } from './logger';

describe('Logger', () => {
  beforeEach(() => {
    vi.clearAllMocks();
    setLogLevel(LogLevel.DEBUG);
  });

  it('should log at different levels', () => {
    const consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
    const logger = createLogger('test');

    logger.debug('debug message');
    logger.info('info message');
    logger.warn('warn message');

    expect(consoleSpy).toHaveBeenCalledTimes(3);
    const output = consoleSpy.mock.calls.map((c) => c[0]).join(' ');
    expect(output).toContain('DEBUG');
    expect(output).toContain('INFO');
    expect(output).toContain('WARN');
  });

  it('should respect log levels', () => {
    const consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
    setLogLevel(LogLevel.WARN);
    const logger = createLogger('test');

    logger.debug('should not show');
    logger.info('should not show');
    logger.warn('should show');

    expect(consoleSpy).toHaveBeenCalledTimes(1);
    expect(consoleSpy.mock.calls[0][0]).toContain('WARN');
  });

  it('should support custom transports', () => {
    const transport = vi.fn();
    addTransport(transport);
    const logger = createLogger('test');

    logger.info('hello transport', { foo: 'bar' });

    expect(transport).toHaveBeenCalledWith(
      expect.objectContaining({
        level: 'INFO',
        message: 'hello transport',
        data: { foo: 'bar' },
        namespace: 'test',
      })
    );
  });

  it('should measure execution time', async () => {
    const logger = createLogger('test');
    const result = await logger.measure('task', async () => {
      await new Promise((r) => setTimeout(r, 10));
      return 'done';
    });

    expect(result).toBe('done');
  });

  it('should be callable as a function (backward compatibility)', () => {
    const consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
    const logger = createLogger('test');

    logger('classic message');

    expect(consoleSpy).toHaveBeenCalled();
    expect(consoleSpy.mock.calls[0][0]).toContain('DEBUG');
    expect(consoleSpy.mock.calls[0][0]).toContain('classic message');
  });
});