esm-logging/tests/unit/logger.test.ts

import {expect, jest, test} from '@jest/globals';
import { Logger, RootLogger, ROOT } from '../../src/logger';
import { Handler } from '../../src/handler';
import { LogRecord } from '../../src/log-record';
import { Formatter } from '../../src/formatter';
import { Manager } from '../../src/manager';
import {
    DEBUG,
    INFO,
    WARNING,
    ERROR,
    CRITICAL,
    NOTSET,
} from '../../src/log-level';
import { MyError } from '../../src/helper/error';

describe('Logger', () => {
    describe('constructor', () => {
        test('sets scope and default level', () => {
            const logger = new Logger('test');
            expect(logger.scope).toBe('test');
            expect(logger.level).toBe(NOTSET);
        });

        test('accepts explicit level', () => {
            const logger = new Logger('test', WARNING);
            expect(logger.level).toBe(WARNING);
        });
    });

    describe('setLevel', () => {
        test('changes the level', () => {
            const logger = new Logger('test');
            logger.setLevel(ERROR);
            expect(logger.level).toBe(ERROR);
        });
    });

    describe('getEffectiveLevel', () => {
        test('returns own level when set', () => {
            const logger = new Logger('test', WARNING);
            expect(logger.getEffectiveLevel()).toBe(WARNING);
        });

        test('returns NOTSET when no level set and no parent', () => {
            const logger = new Logger('test');
            expect(logger.getEffectiveLevel()).toBe(NOTSET);
        });
    });

    describe('isEnabledFor', () => {
        test('returns true when level meets effective level', () => {
            const logger = new Logger('test', DEBUG);
            expect(logger.isEnabledFor(WARNING)).toBe(true);
            expect(logger.isEnabledFor(DEBUG)).toBe(true);
        });

        test('returns false when level is below effective level', () => {
            const logger = new Logger('test', WARNING);
            expect(logger.isEnabledFor(DEBUG)).toBe(false);
            expect(logger.isEnabledFor(INFO)).toBe(false);
        });

        test('caches results for repeated calls', () => {
            const logger = new Logger('test', WARNING);
            const first = logger.isEnabledFor(DEBUG);
            const second = logger.isEnabledFor(DEBUG);
            expect(first).toBe(second);
        });

        test('respects manager disable level', () => {
            const root = new RootLogger(WARNING);
            const manager = new Manager(root);
            const logger = manager.getLogger('test');
            logger.setLevel(DEBUG);
            logger.manager = manager;
            manager.disable = ERROR;
            logger.clear();
            expect(logger.isEnabledFor(DEBUG)).toBe(false);
            expect(logger.isEnabledFor(WARNING)).toBe(false);
            expect(logger.isEnabledFor(CRITICAL)).toBe(true);
        });
    });

    describe('manager property', () => {
        test('starts as null', () => {
            const logger = new Logger('test');
            expect(logger.manager).toBeNull();
        });

        test('can be assigned once', () => {
            const logger = new Logger('test');
            const root = new RootLogger(WARNING);
            const manager = new Manager(root);
            logger.manager = manager;
            expect(logger.manager).toBe(manager);
        });

        test('throws on second assignment', () => {
            const logger = new Logger('test');
            const root = new RootLogger(WARNING);
            const manager = new Manager(root);
            logger.manager = manager;
            expect(() => { logger.manager = manager }).toThrow('logger can only be assigned to manager once');
        });
    });

    describe('addHandler / removeHandler', () => {
        test('adds and removes handlers', () => {
            const logger = new Logger('test');
            const handler = new Handler(DEBUG);
            expect(logger.handlers.length).toBe(0);
            logger.addHandler(handler);
            expect(logger.handlers.length).toBe(1);
            logger.removeHandler(handler);
        });

        test('does not add duplicate handlers', () => {
            const logger = new Logger('test');
            const handler = new Handler(DEBUG);
            logger.addHandler(handler);
            logger.addHandler(handler);
            expect(logger.handlers.length).toBe(1);
        });
    });

    describe('level methods', () => {
        let logger: Logger;
        let emitted: LogRecord[];

        class TestHandler extends Handler {
            emit(record: LogRecord) { emitted.push(record) }
        }

        beforeEach(() => {
            logger = new Logger('test', DEBUG);
            emitted = [];
            logger.addHandler(new TestHandler(DEBUG));
        });

        test('debug emits at DEBUG level', () => {
            logger.debug('msg');
            expect(emitted.length).toBe(1);
            expect(emitted[0].levelno).toBe(DEBUG);
        });

        test('info emits at INFO level', () => {
            logger.info('msg');
            expect(emitted.length).toBe(1);
            expect(emitted[0].levelno).toBe(INFO);
        });

        test('warning emits at WARNING level', () => {
            logger.warning('msg');
            expect(emitted.length).toBe(1);
            expect(emitted[0].levelno).toBe(WARNING);
        });

        test('error emits at ERROR level', () => {
            logger.error('msg');
            expect(emitted.length).toBe(1);
            expect(emitted[0].levelno).toBe(ERROR);
        });

        test('critical emits at CRITICAL level', () => {
            logger.critical('msg');
            expect(emitted.length).toBe(1);
            expect(emitted[0].levelno).toBe(CRITICAL);
        });

        test('level methods respect effective level', () => {
            logger.setLevel(ERROR);
            logger.clear();
            logger.debug('no');
            logger.info('no');
            logger.warning('no');
            expect(emitted.length).toBe(0);
            logger.error('yes');
            logger.critical('yes');
            expect(emitted.length).toBe(2);
        });
    });

    describe('makeRecord', () => {
        test('throws KeyError when extra overwrites existing LogRecord key', () => {
            const logger = new Logger('test', DEBUG);
            expect(() => {
                logger.debug('test', {
                    excInfo: null,
                    extra: { scope: 'override' },
                    stackInfo: false,
                    stackLevel: 1,
                });
            }).toThrow('attempt to overwrite scope in LogRecord');
        });
    });
});

describe('RootLogger', () => {
    test('has scope "root"', () => {
        const root = new RootLogger(WARNING);
        expect(root.scope).toBe('root');
    });

    test('accepts a level', () => {
        const root = new RootLogger(ERROR);
        expect(root.level).toBe(ERROR);
    });
});