TestingLogger

Kind: Class

Source: packages/testing/services/testing-logger.service.ts

Part of: Testing

TestingLogger is a test-focused logger implementation that provides the standard logging methods used throughout the application: log, warn, debug, verbose, and error. It allows tests to capture, inspect, or safely handle log output without depending on the production logging infrastructure.

Extends: ConsoleLogger

Methods

Diagram

mermaid
graph LR
  Test[Test Suite] --> Logger[TestingLogger]
  Logger --> Log[log()]
  Logger --> Warn[warn()]
  Logger --> Debug[debug()]
  Logger --> Verbose[verbose()]
  Logger --> Error[error()]
  Log --> Assertions[Test Assertions]
  Warn --> Assertions
  Debug --> Assertions
  Verbose --> Assertions
  Error --> Assertions

Usage

ts
import { TestingLogger } from '@your-package/testing';

describe('ExampleService', () => {
  it('logs an expected message', () => {
    const logger = new TestingLogger();

    logger.log('Processing started');
    logger.warn('Optional configuration is missing');
    logger.debug('Request payload received');
    logger.verbose('Additional diagnostic details');
    logger.error('Processing failed');

    // Use the testing logger with the service under test.
    // const service = new ExampleService(logger);
  });
});

AI Coding Instructions

• Use TestingLogger when unit or integration tests need a logger dependency instead of the production logger.
• Call the method that matches the intended log level: log for normal messages, warn for recoverable issues, and error for failures.
• Keep test logging deterministic; avoid relying on timestamps, environment-specific values, or external output destinations.
• When adding logger-compatible services, preserve support for all standard methods exposed by TestingLogger.
• Prefer assertions against expected logging behavior when logs represent important operational or error-handling outcomes.

How it works

TestingLogger

TestingLogger is a public class that extends Nest’s ConsoleLogger. Its constructor initializes the inherited logger with the context string "Testing". [packages/testing/services/testing-logger.service.ts:3-9]

Relationships

• IMPORTS → ConsoleLogger