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

import {expect, jest, test} from '@jest/globals';
import { Manager } from '../../src/manager';
import { Logger, RootLogger } from '../../src/logger';
import { Handler } from '../../src/handler';
import { LogRecord } from '../../src/log-record';
import { WARNING, DEBUG, INFO, NOTSET } from '../../src/log-level';

function makeManager(): Manager {
    return new Manager(new RootLogger(WARNING));
}

describe('Manager', () => {
    describe('constructor', () => {
        test('stores the root logger', () => {
            const root = new RootLogger(WARNING);
            const manager = new Manager(root);
            expect(manager.root).toBe(root);
        });
    });

    describe('getLogger', () => {
        test('returns a Logger instance', () => {
            const manager = makeManager();
            const logger = manager.getLogger('app');
            expect(logger).toBeInstanceOf(Logger);
            expect(logger.scope).toBe('app');
        });

        test('returns the same logger for the same scope', () => {
            const manager = makeManager();
            const a = manager.getLogger('app');
            const b = manager.getLogger('app');
            expect(a).toBe(b);
        });

        test('returns different loggers for different scopes', () => {
            const manager = makeManager();
            const a = manager.getLogger('app');
            const b = manager.getLogger('lib');
            expect(a).not.toBe(b);
        });

        test('sets parent to root for top-level loggers', () => {
            const manager = makeManager();
            const logger = manager.getLogger('app');
            expect(logger.parent).toBe(manager.root);
        });

        test('sets parent to existing parent logger', () => {
            const manager = makeManager();
            const parent = manager.getLogger('app');
            const child = manager.getLogger('app.module');
            expect(child.parent).toBe(parent);
        });

        test('establishes hierarchy for deeply nested loggers', () => {
            const manager = makeManager();
            const top = manager.getLogger('a');
            const mid = manager.getLogger('a.b');
            const leaf = manager.getLogger('a.b.c');
            expect(leaf.parent).toBe(mid);
            expect(mid.parent).toBe(top);
            expect(top.parent).toBe(manager.root);
        });

        test('creates placeholders for intermediate loggers', () => {
            const manager = makeManager();
            const leaf = manager.getLogger('a.b.c');
            expect(leaf.parent).toBe(manager.root);

            const mid = manager.getLogger('a.b');
            expect(leaf.parent).toBe(mid);
            expect(mid.parent).toBe(manager.root);
        });

        test('fixes up children when intermediate logger is created', () => {
            const manager = makeManager();
            const leaf = manager.getLogger('a.b.c');
            const top = manager.getLogger('a');

            expect(top.parent).toBe(manager.root);

            const mid = manager.getLogger('a.b');
            expect(leaf.parent).toBe(mid);
        });
    });

    describe('disable', () => {
        test('defaults to 0', () => {
            const manager = makeManager();
            expect(manager.disable).toBe(0);
        });

        test('can be set to a level', () => {
            const manager = makeManager();
            manager.disable = WARNING;
            expect(manager.disable).toBe(WARNING);
        });
    });

    describe('loggerClass', () => {
        test('accepts Logger subclass', () => {
            const manager = makeManager();
            class CustomLogger extends Logger {}
            expect(() => { manager.loggerClass = CustomLogger as any }).not.toThrow();
        });

        test('rejects non-Logger class', () => {
            const manager = makeManager();
            class NotALogger {}
            expect(() => {
                manager.loggerClass = NotALogger as any;
            }).toThrow(TypeError);
        });

        test('accepts Logger itself', () => {
            const manager = makeManager();
            expect(() => { manager.loggerClass = Logger as any }).not.toThrow();
        });
    });

    describe('getLogger - manager assignment', () => {
        test('sets manager on newly created loggers', () => {
            const manager = makeManager();
            const logger = manager.getLogger('app');
            expect(logger.manager).toBe(manager);
        });

        test('sets manager on loggers created from placeholders', () => {
            const manager = makeManager();
            manager.getLogger('a.b.c');
            const mid = manager.getLogger('a.b');
            expect(mid.manager).toBe(manager);
        });

        test('isEnabledFor respects manager.disable via getLogger', () => {
            const manager = makeManager();
            const logger = manager.getLogger('app');
            logger.setLevel(DEBUG);

            expect(logger.isEnabledFor(DEBUG)).toBe(true);

            manager.disable = WARNING;
            logger.clear();

            expect(logger.isEnabledFor(DEBUG)).toBe(false);
            expect(logger.isEnabledFor(WARNING)).toBe(false);
        });
    });

    describe('propagation through hierarchy', () => {
        test('child logger propagates records to parent handler', () => {
            const manager = makeManager();
            const parent = manager.getLogger('app');
            const child = manager.getLogger('app.module');

            parent.setLevel(DEBUG);
            child.setLevel(DEBUG);

            const emitted: string[] = [];
            const handler = new (class extends Handler {
                emit(record: LogRecord) {
                    emitted.push(record.msg);
                }
            })(DEBUG);

            parent.addHandler(handler);
            child.info('propagated message');

            expect(emitted).toContain('propagated message');
        });

        test('child does not propagate to unrelated logger', () => {
            const manager = makeManager();
            const unrelated = manager.getLogger('other');
            const child = manager.getLogger('app.module');

            unrelated.setLevel(DEBUG);
            child.setLevel(DEBUG);

            const emitted: string[] = [];
            const handler = new (class extends Handler {
                emit(record: LogRecord) {
                    emitted.push(record.msg);
                }
            })(DEBUG);

            unrelated.addHandler(handler);
            child.info('should not reach');

            expect(emitted).not.toContain('should not reach');
        });
    });

    describe('clear', () => {
        test('clears logger caches', () => {
            const manager = makeManager();
            const logger = manager.getLogger('test');
            logger.isEnabledFor(DEBUG);
            manager.clear();
        });

        test('does not throw when placeholders exist', () => {
            const manager = makeManager();
            manager.getLogger('a.b.c');
            expect(() => manager.clear()).not.toThrow();
        });
    });
});